Answer:
2.81 g of H2O.
Explanation:
We'll begin by calculating mass of O2 that contains 1.25×10²³ molecules O2.
This can be obtained as follow:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.022×10²³ molecules. This implies that 1 mole of O2 also contains 6.022×10²³ molecules.
1 mole of O2 = 16x2 = 32 g.
Thus 6.022×10²³ molecules is present in 32 g of O2,
Therefore, 1.25×10²³ molecules will be present in =
(1.25×10²³ × 32) / 6.022×10²³ = 6.64 g of O2.
Therefore, 1.25×10²³ molecules present in 6.64 g of O2.
Next, the balanced equation for the reaction. This is given below:
CH4(g) + 2O2(g) —> CO2(g) + 2H2O(g)
Next, we shall determine the masses of CH4 and O2 that reacted and the mass of H2O produced from the balanced equation.
This can be obtained as follow:
Molar mass of CH4 = 12 + (4x1) = 16 g/mol.
Mass of CH4 from the balanced equation = 1 x 16 = 16 g
Molar mass of O2 = 16x2 = 32 g/mol.
Mass of O2 from the balanced equation = 2 x 32 = 64 g
Molar mass of H2O = (2x1) + 16 = 18 g/mol.
Mass of H2O from the balanced equation = 2 x 18 = 36 g
From the balanced equation above,
16 g of CH4 reacted with 64 g of O2 to produce 36 g if H2O.
Next, we shall determine the limiting reactant.
This can be obtained as follow:
From the balanced equation above,
16 g of CH4 reacted with 64 g of O2.
Therefore, 1.25 g of CH4 will react with = (1.25 x 64)/16 = 5 g of O2.
From the above calculations, we can see that only 5 g out of 6.64 g of O2 is needed to react completely with 1.25 g of CH4.
Therefore, CH4 is the limiting reactant.
Finally, we shall determine the mass of H2O produced from the reaction.
In this case, the limiting reactant will be used because it will give the maximum yield of H2O.
The limiting reactant is CH4 and the mass of H2O produced from the reaction can be obtained as follow:
From the balanced equation above,
16 g of CH4 reacted to produce produce 36 g if H2O.
Therefore, 1.25 g of CH4 will react to produce = (1.25 x 36)/16 = 2.81 g of H2O.
Therefore, 2.81 g of H2O were obtained from the reaction.
The mass in grams of H₂O which can be formed when 1.25g CH₄ are combined with 1.25×10²³ molecules O₂ is 2.8 grams.
What is stoichiometry?Stoichiometry of any reaction tells about the amount of species present before and after the completion of the reaction.
Given chemical reaction is:
CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(g)
Moles of CH₄ will b calculate as:
n = W/M, where
W = given mass = 1.25g
M = molar mass = 16g/mol
n = 1.25/16 = 0.078 moles
Molecues of CH₄ in 0.078 moles = 0.078×6.022×10²³ = 0.46×10²³
Given molecules of O₂ = 1.25×10²³
Required molecules of CH₄ is less as compared to the molecules of O₂, so here CH₄ is the limiting reagent and formation of water is depends on it only.
From the stoichiometry of the reaction it is clear that:
1 mole of CH₄ = will produce 2 moles of H₂O
0.078 moles of CH₄ = will produce 2×0.078=0.156 moles of H₂O
Mass of H₂O will be calculated by using its moles as:
W = (0.156)(18) = 2.8g
Hence required mass of H₂O is 2.8g.
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If you had a cup full of methanol and a pool full of methanol, would the mass change?
Answer:
the mass does not change
Explanation:
Given the data: Ag2O(s), = ‑31.1 kJ mol-1, S° = +121.3 J mol-1 K-1 Ag(s), = 0.00 kJ mol-1, S° = +42.55 J mol-1 K-1 O2(g), = 0.00 kJ mol-1, S° = +205.0 J mol-1 K-1 Calculate the temperature at which = 0 for the reaction, Ag2O(s) → 2 Ag(s) + ½ O2(g). Assume that, since the physical states do not change, and are independent of temperature between ‑50.0 °C and 950.0 °C.
Answer:
[tex]T=469.1K\\\\T=195.9\°C[/tex]
Explanation:
Hello,
In this case, for the given decomposition reaction, we can compute the enthalpy of reaction considering the enthalpy of formation of each involved species (products minus reactants):
[tex]\Delta _rH=2\Delta _fH_{Ag}+\frac{1}{2} \Delta _fH_{O_2}-\Delta _fH_{Ag_2O}\\\\\Delta _rH=2*0.00+\frac{1}{2} *0.00-(-31.1)=31.1kJ/mol[/tex]
Next, the entropy of reaction considering the standard entropy for each involved species (products minus reactants):
[tex]\Delta _rS=2S_{Ag}+\frac{1}{2} S_{O_2}-S_{Ag_2O}\\\\\Delta _rS=2(42.55)+\frac{1}{2} (205.0)-(121.3)=66.3J/(mol*K)[/tex]
Next, since the Gibbs free energy of reaction is computed in terms of both the enthalpy and entropy of reaction at the unknown temperature, for such Gibbs energy equaling 0, the temperature (in K and °C) turns out:
[tex]\Delta _rG=\Delta _rH-T\Delta _rS\\\\0=31.1kJ/mol-T(66.3\frac{J}{mol*K}*\frac{1kJ}{1000J} )\\\\T=\frac{31.1kJ/mol}{0.0663kJ/(mol*K)} =469.1K\\\\T=195.9\°C[/tex]
Which is within the given rank.
Best regards.
When the nuclide carbon-14 undergoes beta decay: The name of the product nuclide is . The symbol for the product nuclide is
Answer:
Explanation:
The equation for the decay is given as;
¹⁴₆C --> X + ⁰₋₁e
For conservation of matter, the mass number and atomic number has to be the same in both the reactant and product side f he equation;
Mass number;
14 = x + 0
x = 14
Atomic Number;
6 = x + (-1)
x = 6 + 1 =7
¹⁴₆C --> ¹⁴₇N + ⁰₋₁e
The name of the product nuclide with atomic number of 7 is Nitrogen. The symbol is; ¹⁴₇N
Calculate the energy required to heat 1.30kg of water from 22.4°C to 34.2°C . Assume the specific heat capacity of water under these conditions is 4.18·J·g−1K−1 . Round your answer to 3 significant digits.
Answer:
The energy required to heat 1.30 kg of water from 22.4°C to 34.2°C is 64,121.2 J
Explanation:
Calorimetry is the measurement of the amount of heat that a body gives up or absorbs in the course of a physical or chemical process.
The sensible heat of a body is the amount of heat received or transferred by a body when undergoing a temperature variation (Δt) without there being a change in physical state. That is, when a system absorbs (or gives up) a certain amount of heat, it may happen that it experiences a change in its temperature, involving sensible heat. Then, the equation for calculating heat exchanges is:
Q = c * m * ΔT
Where Q is the heat or quantity of energy exchanged by a body of mass m, constituted by a substance of specific heat c and where ΔT is the variation in temperature (ΔT=Tfinal - Tinitial).
In this case:
[tex]c=4.18 \frac{J}{g*K}[/tex]m= 1.30 kg= 1,300 g (1 kg=1,000 g)ΔT= 34.2 °C - 22.4 °C= 11.8 °C= 11.8 °K Being a temperature difference, it is independent if they are degrees Celsius or degrees Kelvin. That is, the temperature difference is the same in degrees Celsius or degrees Kelvin.Replacing:
[tex]Q=4.18 \frac{J}{g*K}*1,300 g*11.8 K[/tex]
Q= 64,121.2 J
The energy required to heat 1.30 kg of water from 22.4°C to 34.2°C is 64,121.2 J
If a sample of C-14 initially contains 1.6 mmol of C-14, how many millimoles will be left after 2250 years
Answer: 1.2 millimoles will be left after 2250 years
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
[tex]k=\frac{0.693}{5730}=0.00012years^{-1}[/tex]
b) Amount left after 2250 years
[tex]2250=\frac{2.303}{k}\log\frac{1.6}{a-x}[/tex]
[tex]2250=\frac{2.303}{0.00012}\log\frac{1.6}{a-x}[/tex]
[tex]\log\frac{1.6}{a-x}=0.117[/tex]
[tex]\frac{1.6}{a-x}=1.31[/tex]
[tex]{a-x}=\frac{1.6}{1.31}=1.2[/tex]
Thus 1.2 millimoles will be left after 2250 years
"What is the difference between the revertible and nonrevertible rII mutants that Benzer generated?"
A chemist prepares a solution of silver(I) nitrate(AgNO3) by measuring out 269. mu mol of silver(I) nitrate into a 300. mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in mmol/L of the chemist's silver(I) nitrate solution.
Answer:
concentration in mmol/L = 8.97 × 10⁻¹ mmol/L
Explanation:
Given that:
the number of moles of silver(I) nitrate(AgNO3) the chemist used in preparing a solution = 269 mmol = 269 × 10⁻³ mmol
The volume of the volumetric flask = 300 mL = 300 × 10⁻³ L
In order to calculate the concentration in mmol/L of the chemist's silver(I) nitrate (AgNO3) solution , we used the formula which can be expressed as;
[tex]concentration \ in \ mmol/L = \dfrac{ number \ of \ mmol}{vol. \ of \ the \ solution}[/tex]
[tex]concentration \ in \ mmol/L = \dfrac{ 269 * 10^{-3 } \ mmol }{300 * 10^{-3} \ L }[/tex]
concentration in mmol/L = 0.8966 mmol/L
concentration in mmol/L = 8.97 × 10⁻¹ mmol/L
Which element always exists in monatomic form? silicon, a metalloid oxygen, a nonmetal calcium, a metal neon, a noble gas
Answer:
[tex]\huge\boxed{A \ noble \ gas}[/tex]
Explanation:
A noble gas always exists in a mono-atomic form. This is because the valency of noble gas is zero and thus they don't tend to lose, gain or share electrons. They are inert gases and do not react.
Answer:
a noble gas
Explanation:
the the noble gases exist as mono atomic elements that is helium, neon ,argon, Krypton,etc.
mono atomic elements exist as stable single atoms
g Does a reaction occur when aqueous solutions of barium hydroxide and aluminum sulfate are combined
Answer:
3BaO + Al₂(SO₄)₃ → Al₂O₃+ 3BaSO₄
Explanation:
Yes! A reactiin occurs between barium hydroxide and auminium sulphate.
barium sulfate (BaSO4) and aluminum hydroxide (Al(OH)3) are the products obtained in this reaction.
The reaction is given by the equation below;
3BaO + Al₂(SO₄)₃ → Al₂O₃+ 3BaSO₄
Compare and contrast an electrolytic cell with a voltaic cell. Provide one example where both are present in daily life.
Answer:
ELECTROLYTIC CELL
An electrochemical cell in which a non-spontaneous chemical reaction takes place when electric current is passed through the solution,is called an electrolytic cell.
EXAMPLE
Nelsons cell and Downs cell
VOLTAIC CELL OR GALVANIC CELL
The electrochemical cell in which a spontaneous chemical reaction takes place and generates electric current is called galvanic and voltaic cell.
EXAMPLE
Daniel cell
Explanation:
Electrolytic cell by the non-spontaneous reactions covert the chemical energy into electical and volataic cells are those in which spontaneous redox reaction takes place.
What is cell?Cell is a device which converts chemical energy into electrical energy.
Electrolytic Cell: An electrolytic cell is an electrochemical cell in which a non-spontaneous redox chemical reaction occurs when an electric current is conducted through the solution.
Example- Electrolysis of sodium chloride, by which formation of sodium metal and chlorine gas takes place.
Voltaic cell: Voltaic cells are electrochemical cells in which a spontaneous redox chemical reaction occurs and creates electric current. These cells are also known by the name of Galvanic cells.
Example- It is used in the form of batteries which can be portable easily.
Hence, in electrolytic cells non - spontaneous reaction occur and in voltaic cell spontaneous reaction is occured.
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What is the oxidizing agent in the redox reaction represented by the following cell notation? Ni(s) | Ni2+(aq) || Ag+(aq) | Ag(s)
Answer:
Silver.
Explanation:
Hello,
In this case, for the redox reaction:
[tex]Ni^0(s)+Ag^+(aq)\rightarrow Ni^{2+}+Ag^0(s)[/tex]
We can see the nickel is being oxidized as its oxidation state increases from 0 to 2+ whereas the oxidation state of silver decreases from +1 to 0, it means that the oxidizing agent is silver and the reducing agent is nickel.
Best regards.
The oxidizing agent in the redox reaction represented by the following cell notation is Silver.
Calculation of the oxidizing agent:The redox reaction is
Ni(s) | Ni2+(aq) || Ag+(aq) | Ag(s)
here the nickel is being oxidized since its oxidation state rises from 0 to 2+ while on the other hand, the oxidation state of silver is reduced from +1 to 0, it means that the oxidizing agent is silver and the reducing agent is nickel.
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What is advertising used for? Check all that apply. influencing consumer tastes tracking product popularity increasing product awareness promoting company branding gathering data about potential consumers
Answer:
influencing consumer tastes
increasing product awareness
promoting company branding
Explanation:
Advertising is basically a form of communication using creative ideas and communicating benefits of the products. Advertising plays a very crucial role in product business and some of the important uses of advertising are as follows:
Creative advertisements, influence customers or consumers to buy the product.Advertisings involve information regarding the product and so increases product awareness.Advertising on social media platforms, TVs, radio and newspapers, promotes company branding.Hence, the correct options are:
influencing consumer tastesincreasing product awarenesspromoting company branding
Answer:
1,3,4
Explanation:
I took the test
A reaction mechanism has the following proposed elementary steps:Step 1: A → B + CStep 2: A + B → DStep 3: 2 A + D → C + EIf Step 2 is the rate-limiting step, what would the proposed rate law for this mechanism be?
Answer: [tex]Rate=k[A][B][/tex]
Explanation:
Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.
Order of the reaction is defined as the sum of the concentration of terms on which the rate of the reaction actually depends. It is the sum of the exponents of the molar concentration in the rate law expression.
For reactions which takes place in multiple steps are complex reactions and the order is given by the slowest step which is the rate limiting step.
For the given reaction, the rate limiting step is
[tex]A+B\rightarrow D[/tex]
Rate law will be , [tex]Rate=k[A][B][/tex]
GIVING 100 POINTS PLEASE ANSWER SOON When ponds freeze, they freeze at the surface first before freezing at the bottom. Which property of water explains why this might happen? Density Adhesion High boiling point High specific heat
Answer:
[tex]\huge\boxed{Density}[/tex]
Explanation:
This is because of density. Since Ice is less dense than water, the ice even formed inside the pond then starts floating on the surface of water. Because of this density, Ice floats on water and thus the water freezes at the surface.
Answer:
Density
Explanation:
Water is less dense as a solid than as a liquid, so as ponds freeze, the ice floats at the top and the pond freezes from the top-down.
A student mixes 1.0 mL of aqueous silver nitrate, AgNO3 (aq), with 1.0 mL of aqueous sodium chloride, NaCl (aq), in a clean test tube. What will the student observe
Answer:
AgCl (silver Chloride) is being precipitated out as white and cloudy crystals.
Explanation:
If a student mixes 1.0 mL of aqueous silver nitrate AgNO3 (aq) with 1.0 mL of aqueous sodium chloride, NaCl (aq), in a clean test tube.
The sodium chloride is being acidified with dilute trioxonitrate (V) acid. Then a few drops of silver trioxonitrate(V) is added afterwards. A white precipitate of silver chloride, which dissolves readily in aqueous ammonia indicates the presence of sodium chloride.
The reaction proceeds as follows:
[tex]\mathtt{AgNO_{3(aq)} + NaCl _{(aq)} \to AgCl _{(s)} + NaNO_3_{(aq)}}[/tex]
From the reaction between AgNO3 (aq) and NaCl (aq), AgCl (silver Chloride) is being precipitated out as white and cloudy crystals.
When methane is burned with oxygen, the products are carbon dioxide and water. If you produce 9 grams of water and 11 grams of carbon dioxide from 16 grams of oxygen, how many
The given question is incomplete.
The complete question is:
When methane is burned with oxygen, the products are carbon dioxide and water. If you produce 9 grams of water and 11 grams of carbon dioxide from 16 grams of oxygen, how many grams of methane were needed for the reaction?
Answer: 4 grams of methane were needed for the reaction
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
{tex]CH_4+2O_2\rightarrow CO_2+H_2O[/tex]
Given: mass of oxygen = 16 g
Mass of carbon dioxide = 11 g
Mass of water = 9 g
Mass of products = Mass of carbon dioxide + mass of water = 11 g +9 g = 20 g
Mass or reactant = mass of methane + mass of oxygen = mass of methane + 16 g
As mass of reactants = mass of products
mass of methane + 16 g= 20 g
mass of methane = 4 g
Thus 4 grams of methane were needed for the reaction
Write the half-reactions as they occur at each electrode and the net cell reaction for this electrochemical cell containing indium and cadmium. In(s)|
Answer:
Oxidation half equation;
3Cd(s) -------> 3Cd^2+(aq) + 6e
Reduction half equation;
2In^3+(aq) + 6e -----> 2In(s)
Explanation:
Since the reduction potentials of Indium and Cadmium are -0.34 V and - 0.40 V respectively, we can see that cadmium will be oxidized while indium will the reduced.
We arrived at this conclusion by examining the reduction potential of both species. The specie with more negative reduction potential is oxidized in the process.
Oxidation half equation;
3Cd(s) -------> 3Cd^2+(aq) + 6e
Reduction half equation;
2In^3+(aq) + 6e -----> 2In(s)
In the Lewis structure of AB4 where B is more electronegative than A. Both are main group elements where A has 8 valence electrons and each B has 7 valence electrons.
Required:
a. What is the total number of valence electrons?
b. How many lone pairs are in the molecule?
Answer:
1. 36
2. Two
Explanation:
The Lewis structure shows the valence electrons present in a compound. Usually the valence electrons are shown as dot structures around the symbol of the elements involved in the compound.
For a compound AB4 where B is more electronegative than A and A has 8 electrons in its valence shell, there will be thirty six valence electrons on the outermost shell of the molecule.
There are six electron pair domains present in the molecule, four bond pairs and two lone pairs. The molecule is in a square planar geometry.
Answer: a- 36 valence electrons
b- 14 lone pairs
Explanation:
Valence is equal to A + 4B = 8 + 4(7)
With 4 bonds between A and the 4 B, that is 36 valence minus 8 electrons in those pairs = 28. 28 is 14 lone pairs.
Determine the percent water in Cuso4.5H20 to 3 significant figures
Answer:
Molar mass is the mass of one mole of a substance and is ontained by adding atomic mases of all the constituent atoms and group of atoms.
Atomic masses: Cu = 63.55 g/mol,
S = 32.07 g/mol
O x 4 = 16.00 g/mol x 4 = 64.00 g/mol
H = 1.008 g/mol,
So, H2O = (2*1.008+16.00)*5 = 90.10 g/mol
Molar mass of CuSO4,5H2O = 249.72 g/mol.
Out of that 249.72 grams, 90.10 grams is water,
So, percentage by mass of water in CuSO4,5H2O
= 90.10*100/249.72 = 36.08.
I think this is what you are asking. hope this helps
Plzzz help and solve this using factor labeling
Answer:
there are 37,8541 liters in 10 gallons
We discussed the different types of intermolecular forces in this lesson, which can affect the boiling point of a substance.
1. Which of these has the highest boiling point?
A) Ar
B) Kr
C) Xe
D) Ne
2. Which substance has the highest boiling point?
A) CH4
B) He
C) HF
D) Cl2
Answer:
1, C, Xe 2, B,He
Explanation:
1, cause as u go down a group the boiling point increases.
2, boiling point of single element is greater than a compound
According to periodic trends in periodic table boiling point increases down the group and hence Xe has highest boiling point and more amount of heat is required to boil an element hence He has highest boiling point.
What is periodic table?
Periodic table is a tabular arrangement of elements in the form of a table. In the periodic table, elements are arranged according to the modern periodic law which states that the properties of elements are a periodic function of their atomic numbers.
It is called as periodic because properties repeat after regular intervals of atomic numbers . It is a tabular arrangement consisting of seven horizontal rows called periods and eighteen vertical columns called groups.
Elements present in the same group have same number of valence electrons and hence have similar properties while elements present in the same period show gradual variation in properties due to addition of one electron for each successive element in a period.
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Draw two constitutional isomers that share the molecular formula C3H8S. Your structures will have the same molecular formula but will have different connectivities.
Answer:
Two constitutional isomers for the compound C3H8S are shown in the attachment below
Explanation:
Constitutional isomers are isomers that have the same molecular formula but different connectivity. Two constitutional isomers for the compound C3H8S are shown in the attachment below.
As per the concept of structural isomers, the two constitutional isomers that share the molecular formula C₃H₈S are attached in attachment below.
Structural isomers are defined as the isomers in which atoms are completely arranged in a different order but the molecular formula remains the same.
They are the molecules which have same molecular formula but different connectivities of atoms which depend on the order they are put together. An increase in the number of carbon atoms leads to an increase in the structural isomers.
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g The electronic structure of which ONE of the following species cannot be adequately described by a single Lewis formula? (In other words, the electronic structure of which one can only be described by drawing two or more resonance structures?) A) C2H4 B) SO3 2– C) SO3 D) C3H8 E) HCN
Answer:
C) SO3
Explanation:
Lewis formula shows the bonding between atoms of a molecule and expresses the lone pair present in the atoms.
SO3 or Sulfur trioxide cannot be adequately described by a single Lewis formula because it has majorly 3 resonance structures because Sulfur does not follow the octet rule and can expand electrons in its outer shell.
Hence, the correct answer is C) SO3
A 1.00 liter flask initially contained 0.24 mol NO2 at 700 K which decomposed according to the following equation. When equilibrium was achieved, 0.14 mol NO was present. Calculate Kc. 2NO2(g) ↔ 2NO(g) + O2(g)
Answer:
[tex]Kc=0.14[/tex]
Explanation:
Hello,
In this case, for the given reaction, the equilibrium expression is:
[tex]Kc=\frac{[NO]^2[O_2]}{[NO_2]^2}[/tex]
That in terms of the reaction extent [tex]x[/tex] is written as (initial concentration of NO2 is 0.24 M for 0.24 mol in 1.00 L):
[tex]Kc=\frac{(2*x)^2(x)}{(0.24M-2*x)^2}[/tex]
Moreover, since at the equilibrium 0.14 moles of NO are present (a 0.14-M concentration), we can compute the reaction extent as shown below:
[tex][NO]=2*x=0.14M[/tex]
[tex]x=0.14M/2=0.07M[/tex]
In such a way, knowing [tex]x[/tex], we compute Kc as shown below:
[tex]Kc=\frac{(2*0.07)^2(0.07)}{(0.24M-2*0.07)^2}\\\\Kc=0.14[/tex]
Regards.
The kc is 0.14.
Equivalent expression:Since
[tex]Kc = \frac{[NO]^2[O_2]}{[NO_2]^2}\\\\[/tex]
Here the reaction extent x should be written like the initial concentration of NO2 is 0.24 M for 0.24 mol in 1.00 L.
Now
[tex]Kc = \frac{(2\times\ x)^2}{(0.24M - 2\times x)^2}[/tex]
Since at the equilibrium 0.14 moles of NO are presented so the reaction should be
NO = 2*x = 0.14m
x = 0.07
Now kc should be
[tex]= \frac{(2\times 0.07)^2 (0.07)}{(0.24M - 2\times 0.07)^2}[/tex]
= 0.14
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A sample of carbon dioxide gas has a density of g/L at a pressure of 0.889 atm and a temperature of 55.0 °C. Assume ideal behavior,occupies a volume of 686 mL. If the gas is heated at constant pressure until its volume is 913 mL, the temperature of the gas sample will be:_______ ? °C.
Answer:
163.5 °C
Explanation:
The following data were obtained from the question:
Initial volume (V1) = 686 mL.
Initial temperature (T1) = 55 °C.
Final volume (V2) = 913 mL
Initial pressure (P1) = final pressure (P2) = 0.889 atm
Final temperature (T2) =.?
Next, we shall convert celsius temperature to Kelvin temperature.
This can be done as shown below:
Temperature (K) = Temperature (°C) + 273
T(K) = T (°C) + 273
Initial temperature (T1) = 55 °C.
Initial temperature (T1) = 55 °C + 273
Initial temperature (T1) = 328 K
Next, we shall determine the new temperature of the gas.
Since the pressure is constant, we shall determine the new temperature as follow:
V1/T1 = V2 /T2
Initial volume (V1) = 686 mL.
Final volume (V2) = 913 mL
Initial temperature (T1) = 328 K
Final temperature (T2) =.?
V1/T1 = V2 /T2
686/328 = 913/T2
Cross multiply
686 x T2 = 328 x 913
Divide both side by 686
T2 = (328 x 913)/686
T2 = 436.5 K
Finally, we shall convert Kelvin temperature to celsius temperature.
This can be done as shown below:
Temperature (°C) = Temperature (K) – 273
T (°C) = T(K) – 273
T(K) = 436.5 K
T (°C) = 436.5 – 273
T (°C) = 163.5 °C
Therefore, the temperature of the gas sample is 163.5 °C.
Determine whether the following statement about reaction rates is true or false. If the statement is false, select the reason why?
Increasing the temperature of a reaction system decreases the activation energy of the reaction.
Answer:
False
Explanation:
Reaction rates is a field under chemical kinetics that deals with the measure of speed of a chemical reaction. It is the change in the concentration of a reactant or product per unit time.
Activation Energy is a theory been put forward to explain why different chemical reactions proceed at different rates.
Activation Energy theory postulates that for a reactant to transform into a product , the colliding particles or molecules of the reactant must possess a certain amount of energy so as to overcome the reaction barrier.
An important factor which may influence the attainment of activation energy by colliding particles of reactants is the temperature at which the reaction is carried out. The higher the temperature, the greater is the fraction of the reactant particles which possess the activation energy and thus the faster the reaction becomes. SO , in essence increasing the temperature of a reaction system do not decreases the activation energy of the reaction but rather also increases the activation energy of the reaction.
An enzyme is discovered that catalyzes the chemical reaction:SAD -------->HAPPY
<-------A team of motivated researchers sets out to study the enzyme which they call Happyase. They find that the Kcat for happyase is 600s-1. They carry out several experiments. When [Et]=20 nM and [SAD]=40 \mu M, the reaction velocity, Vo is 9.6 \mu Ms^{-1} . Calculate the Km for the substrate SAD.
Answer: Km = 10μM
Explanation: Michaelis-Menten constant (Km) measures the affinity a enzyme has to its substrate, so it can be known how well an enzyme is suited to the substrate being used. To determine Km another value associated to an eznyme is important: Turnover number (Kcat), which is the number of time an enzyme site converts substrate into product per unit time.
Enzyme veolcity is calculated as:
[tex]V_{0} = \frac{E_{t}.K_{cat}.[substrate]}{K_{m}+[substrate]}[/tex]
where Et is concentration of enzyme catalitic sites and has to have the same unit as velocity of enzyme, so Et = 20nM = 0.02μM;
To calculate Km:
[tex]V_{0}*K_{m} + V_{0}*[substrate] = E_{t}.K_{cat}.[substrate][/tex]
[tex]K_{m} = \frac{E_{t}.K_{cat}.[substrate]-V_{0}*[substrate]}{V_{0}}[/tex]
[tex]K_{m} = \frac{0.02*600*40-9.6*40}{9.6}[/tex]
Km = 10μM
The Michaelis-Menten for the substrate SAD is 10μM.
Why can long chain fatty acids can form micelles in solutions with pH > 7 but are insoluble in pH < 5
Answer:
In basic conditions that is ( pH > 7 ), the equilibrium shifts towards right and produces a lot of (-ve) negatively charged fatty acids which are polar, In water, since they have long hydrophobic hydrocarbon part, this form micelles where the hydrocarbon part remain inside the sphere and -coo- group remain outside the sphere due to H-bonding interaction with water.
At ( pH < 5 ) I.e acidic conditions, the equilibrium shift to the left giving neutral molecules which can not have stronger H-bonding interaction .
So micelles cant form as they become insoluble.
Calculate the amount of heat that must be absorbed by 10.0 g of ice at –20°C to convert it to liquid water at 60.0°C. Given: specific heat (ice) = 2.1 J/g·°C; specific heat (water) = 4.18 J/g·°C; ΔH fus = 6.0 kJ/mol.
Answer:
The amount of heat to absorb is 6,261 J
Explanation:
Calorimetry is in charge of measuring the amount of heat generated or lost in certain physical or chemical processes.
The total energy required is the sum of the energy to heat the ice from -20 ° C to ice of 0 ° C, melting the ice of 0 ° C in 0 ° C water and finally heating the water to 60 ° C.
So:
Heat required to raise the temperature of ice from -20 °C to 0 °CBeing the sensible heat of a body the amount of heat received or transferred by a body when it undergoes a temperature variation (Δt) without there being a change of physical state (solid, liquid or gaseous), the expression is used:
Q = c * m * ΔT
Where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation (ΔT=Tfinal - Tinitial).
In this case, m= 10 g, specific heat of the ice= 2.1 [tex]\frac{J}{g*C}[/tex] and ΔT=0 C - (-20 C)= 20 C
Replacing: Q= 10 g*2.1 [tex]\frac{J}{g*C}[/tex] *20 C and solving: Q=420 J
Heat required to convert 0 °C ice to 0 °C waterThe heat Q necessary to melt a substance depends on its mass m and on the called latent heat of fusion of each substance:
Q= m* ΔHfusion
In this case, being 1 mol of water= 18 grams: Q= 10 g*[tex]6.0 \frac{kJ}{mol} *\frac{1 mol of water}{18 g}[/tex]= 3.333 kJ= 3,333 J (being kJ=1,000 J)
Heat required to raise the temperature of water from 0 °C to 60 °CIn this case the expression used in the first step is used, but being: m= 10 g, specific heat of the water= 4.18 [tex]\frac{J}{g*C}[/tex] and ΔT=60 C - (0 C)= 60 C
Replacing: Q= 10 g*4.18 [tex]\frac{J}{g*C}[/tex] *60 C and solving: Q=2,508 J
Finally, Qtotal= 420 J + 3,333 J + 2,508 J
Qtotal= 6,261 J
The amount of heat to absorb is 6,261 J
The amount of heat to absorb is 6,261 J.
Calculation for heat:Heat required to raise the temperature of ice from -20 °C to 0 °C.
The formula for specific heat is used to calculate the amount of heat
Q = c * m * ΔT
Where,
Q =heat exchanged by a body,
m= mass of the body
c= specific heat
ΔT= change in temperature
Given:
m= 10 g,
specific heat of the ice= 2.1
ΔT=0 C - (-20 C)= 20 C
On substituting the values:
Q= 10 g*2.1 *20 C
Q=420 J
Heat required to convert 0 °C ice to 0 °C water.
The heat Q necessary to melt a substance depends on its mass m and on the called latent heat of fusion of each substance:
Q= m* ΔHfusion
Heat required to raise the temperature of water from 0 °C to 60 °C
m= 10 g,
Specific heat of the water= 4.18
ΔT=60 C - (0 C)= 60 C
On substituting:
Q= 10 g*4.18 *60 C
Q=2,508 J
Thus, Qtotal= 420 J + 3,333 J + 2,508 J
Qtotal= 6,261 J
The amount of heat to absorb is 6,261 J
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How many equivalent resonance structures can be drawn for the molecule of SO3 without having to violate the octet rule on the sulfur atom
Answer:
3
Explanation:
Resonance is a valence bond concept put forward by Linus Pauling to explain the fact that the observed properties of a molecule may be as a result of the fact that its actual structure lie somewhere between a given number of structural extremes called canonical structures or resonance structures.
There are three resonance structures for SO3 that obey the octet rule. All the S-O bonds in SO3 are equivalent in these resonance structures.
Seven equivalent resonance structures for the molecular of SO3 can be drawn without breaking the octet rule.
We can arrive at this answer because:
The octet rule is a rule that states that an atom must reach stability when it has eight electrons in the valence layer.This means that in bonds that cause the donation or sharing of electrons between atoms, each atom has eight electrons in the valence layer.In chemistry, resonance is a term that refers to structures created to represent the donation or sharing of electrons between the atoms of a molecule.These structures can be arranged in different ways, as long as they respect the octet rule.In an SO3 molecule, electrons are shared between atoms. This sharing can be done with seven resonance structures.
These structures are shown in the figure below.
More information:
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