Answer:
Jesseca Kusher, an 18-year-old researcher from Spartansburg, S.C., invented a paint-on coating for roofing shingles. Her formula could reduce a home's cooling costs and possibly cut ozone pollution in urban areas...
SUPPORT ME ...........
Answer:
Jesseca created mixtures containing graphite, gypsum, and mica that could be painted on roof shingles.
Explanation:
Hope this helped!!
A solution of LiCl in water has XLiCl = 0.0800. What is the molality? A solution of LiCl in water has XLiCl = 0.0800. What is the molality? 4.44 m LiCl 8.70 m LiCl 4.83 m LiCl 4.01 m LiCl
Answer:
mol LiCl = 4.83 m
Explanation:
GIven:
Solution of LiCl in water XLiCl = 0.0800
Mol of water in kg = 55.55 mole
Find:
Molality
Computation:
mole fraction = mol LiCl / (mol water + mol LiCl)
0.0800 = mol LiCl / (55.55 mol + mol LiCl)
0.0800 mol LiCl + 4.444 mol = mol LiCl
mol LiCl - 0.0800 mol LiCl = 4.444 mol
0.92 mol LiCl = 4.444 mol
mol LiCl = 4.83 m
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.
what is the oxidation state of the oxygen atoms in co2,h2o and o2 and what does this information tell you about photosynthesis and respiration
Answer:
-2, -2 and 0.
- Respiration is a process in which energy is produced and photosynthesis is a process in which energy is used.
Explanation:
Hello,
In this case, oxygen is a substance that is used for animals and us to acquire the energy necessary for several functions by the cellular respiration (we also need glucose), besides, it is a product of the photosynthesis carried out by vegetable cells (plants). Moreover, carbon dioxide and water are used by the plants to produce oxygen we need as well as glucose via the aforementioned photosynthesis, thus, both chemical reactions are shown below:
[tex]C_6H_{12}O_6+6O_2\rightarrow 6CO_2+6H_2O\ \ \ respiration\\\\6CO_2+6H_2O\rightarrow C_6H_{12}O_6+6O_2\ \ \ photosynthesis[/tex]
In such a way, since the oxygen in carbon dioxide and water has an oxidation state of -2 (reduced form) we can say that the respiration is a process in which energy is produced and since the oxygen yielded during the photosynthesis has an oxydation state of 0, we can say that photosynthesis is a process in which energy is used.
Best regards.
Calculate the entropy change in the surroundings associated with this reaction occurring at 25∘C. Express the entropy change to three significant figures and include the appropriate units.
Answer:
That means that if you are calculating entropy change, you must multiply the enthalpy change value by 1000. So if, say, you have an enthalpy change of -92.2 kJ mol-1, the value you must put into the equation is -92200 J mol-1
The entropy change in the surroundings associated with this reaction occurring at 25 degree C is calculated as ΔS = -ΔH/T J/K.
What is entropy?Entropy is a quantity which gives idea about the randomness or arrangement of atoms or molecules present in any sample.
Entropy change will be calculated as:
ΔS = -ΔH/T, where
ΔH = chnage in enthalpy (J/mole)
T = temperature (K)
So to calculate the entropy change first we have to know about the value of enthalpy in joules and then divide it by the temperature.
Hence the unit of entropy is joule per kelvin.
To know more about entropy, visit the below link:
https://brainly.com/question/6364271
A 30.5 g sample of a compound contains 9.29 g of nitrogen and the rest is oxygen. What is the empirical formula of the compound?
Answer:
The empirical formula of the compound is NO2.
Explanation:
The following data were obtained from the question:
Mass of compound = 30.5 g
Mass of nitrogen (N) = 9.29 g
Empirical formula of compound =?
Next, we shall determine the mass of oxygen in the compound. This can be obtained as follow:
Mass of compound = 30.5 g
Mass of nitrogen (N) = 9.29 g
Mass of oxygen (O) =?
Mass of O = mass of compound – mass of N.
Mass of O = 30.5 – 9.29
Mass of O = 21.21 g
Finally, we shall determine the empirical formula of the compound as follow:
Mass of nitrogen (N) = 9.29 g
Mass of oxygen (O) = 21.21 g
Divide by their molar mass.
N = 9.29 / 14 = 0.664
O = 21.21 / 16 = 1.326
Divide by the smallest
N = 0.664/ 0.664 = 1
O = 1.326/ 0.664 = 2
Therefore the empirical formula of the compound is NO2.
When 5.58g H2 react by the following balanced equation, 32.8g H2O are formed. What is the percent yield of the reaction? 2H2(g)+O2(g)⟶2H2O(l)
A) 11.7%
B) 17.0%
C) 38.9%
D) 65.7%
Answer:
D) 65.7%
Explanation:
Based on the reaction:
2H2(g)+O2(g)⟶2H2O(l)
2 moles of hydrogen produce 2 moles of water assuming an excess of oxygen.
To find percent yield of the reaction we need to find theoretical yield (The yield assuming all hydrogen reacts producing water). With theoretical yield and actual yield (32.8g H₂O) we can determine percent yield as 100 times the ratio between actual yield and theoretical yield.
Theoretical yield:
Moles of 5.58g H₂:
5.58g H₂ ₓ (1 mol / 2.016g) = 2.768 moles H₂
As 2 moles of H₂ produce 2 moles of H₂O, if all hydrogen reacts will produce 2.768 moles H₂O. In grams:
2.768 moles H₂O ₓ (18.015g / mol) =
49.86g H₂O is theoretical yield
Percent yield:
Percent yield = Actual yield / Theoretical yield ₓ 100
32.8g H₂O / 49.86g ₓ 100 =
65.7% is percent yield of the reaction
D) 65.7%A galvanic cell consists of a Cu(s)|Cu2+(aq) half-cell and a Cd(s)|Cd2+(aq) half-cell connected by a salt bridge. Oxidation occurs in the cadmium half-cell. The cell can be represented in standard notation as
Answer:
[tex]Cd(s)|Cd^{2+}(aq) || Cu^{2+}(aq)|Cu(s)[/tex]
Explanation:
A galvanic cell is composed of two electrodes immersed in a suitable electrolyte and connected via a salt bridge. One of the electrodes serves as a cathode where reduction or gain of electrons takes place. The other half cell functions as an anode where oxidation or loss of electrons occurs.
The representation is given by writing the anode on left hand side followed by its ion with its molar concentration. It is followed by a salt bridge. Then the cathodic ion with its molar concentration is written and then the cathode.
As it is given that cadmium acts as anode, it must be on the left hand side and copper must be on right hand side.
[tex]Cd(s)|Cd^{2+}(aq) || Cu^{2+}(aq)|Cu(s)[/tex]
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.
A. True
B. False
Answer:
False
Explanation:
The reaction rate increases if the temperature also increases, as does the concentration of ractives or the presence of catalysts.
The reaction rate talks about how reagents are converted into products as a function of time, this process can take less or more depending on the factors to which the reaction is exposed.
The increasing temperature generates an increase in the kinetic energy of the particles, promoting their proximity and their reaction between them to be able to give the final product, so a faster reaction occurs, which is why it has promoted when the particles collide.
What is the concentration in ppm of 4 g of NaCl dissolved in 100 mL of water?
If an individual proton has mass 1.007825 amu, and an individual neutron has mass 1.008665 amu, what's the calculated mass of a neptunium-236 nucleus? options: A) 237.92482 amu B) 236.99873 amu C) 237.96682 amu D) 237.04817 amu
Answer:
C) 237.96682 amu
Explanation:
The symbol for neptunium-236 is given as;
²³⁶₉₃Np
This element has 93 protons and (236 - 93 = 143) neutrons.
Mass Number =Total mass of Protons + Total mass of neutrons
Total Mass pf protons = 93 * 1.007825 amu, = 93.727725 amu
Total mass of Neutrons = 143 * 1.008665 amu = 144.239095 amu
Mass = 144.239095 + 93.727725 = 237.96682 amu
Correct option is option C.
There are 454 grams in one pound. How many pounds are in 700 grams
Answer:
1.543 pounds = 700 grams
If there are a 1000 ml per 1 L and a 1000g per kilogram
a. How many ml are there in 5.0 L?
b. How many kg are there in 230g?
Answer:
hbchbjH j jas a aa a s ds d as das
Explanation:
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)
when the temperature of an ideal gas is increased from 27C to 927C then kinetic energy increases by
Answer:
The rms speed of its molecules becomes. (T) has become four times. Therefore, v_(rms) will become two times,...
g Which ONE of the following molecules and ions has trigonal planar molecular geometry? (NOTE: You must first determine what the Lewis structure of each substance is.) A) PCl3 B) HCN C) CO3 2– D) H3O+ E) NF3
Answer: C) [tex]CO^{2-}_{3}[/tex]
Explanation: The Valence Shell Electron Pair Repulsion Model (VSEPR Model) shows bonding and nonbonding electron pairs present in the valence, outermost, shell of an atom connecting to other atoms. It also gives the molecular geometric shape of a molecule.
To determine molecular geometry:
1) Draw Lewis Structure, i.e., a simplified representation of the valence shell electrons;
2) Count the number of electron pairs (count multiple bonds as 1 pair);
3) Arrange electron pairs to minimise repulsion;
4) Position the atoms to minimise the lone pair;
5) Name the molecular geometry from the atom position;
Trigonal planar molecular geometry is a model which molecule's shape is triangular and in one plane. Such molecule has three regions of electron density extending out from the central atom and the repulsion will be at minimum when angle between any two is 120°.
The Lewis structure of each molecule is shown in the attachment.
Analysing each one, it can be concluded that molecule with trigonal planar geometry is [tex]CO^{2-}_{3}[/tex]
Calculate the number of hydrogen atoms in a 110.0 sample of tetraborane(B4H10) . Be sure your answer has a unit symbol if necessary, and round it to 4 significant digits.
Answer:
[tex]1.242 \times 10^{25}\text{ atoms H}[/tex]
Explanation:
You must convert the mass of B₄H₁₀ to moles of B₄H₁₀, then to molecules of B₄H₁₀, and finally to atoms of H.
1. Moles of B₄H₁₀
[tex]\text{Moles of B$_{4}$H}_{10} = \text{110.0 g B$_{4}$H}_{10} \times \dfrac{\text{1 mol B$_{4}$H}_{10}}{\text{53.32 g B$_{4}$H}_{10}} = \text{2.063 mol B$_{4}$H}_{10}[/tex]
2. Molecules of B₄H₁₀
[tex]\text{No. of molecules} = \text{2.063 mol B$_{4}$H}_{10} \times \dfrac{6.022 \times 10^{23}\text{ molecules B$_{4}$H}_{10}}{\text{1 mol B$_{4}$H}_{10}}\\\\=1.242 \times 10^{24}\text{ molecules B$_{4}$H}_{10}[/tex]
3. Atoms of H
[tex]\text{Atoms of H} = 1.242 \times 10^{24}\text{ molecules B$_{4}$H}_{10} \times \dfrac{\text{10 atoms H}}{\text{1 molecule B$_{4}$H}_{10}}\\\\= \mathbf{1.242 \times 10^{25}}\textbf{ atoms H}[/tex]
How are pH and pOH ?
A. pH = 14 + pOH
B. pOH = 14 - pH
C. pOH = 14 + pH
D. pH = 14 - pOH
Answer:
B. pOH = 14 - pH and D. pH = 14 - pOH.
Explanation:
Hello,
In this case, we must remember that pH and pOH are referred to a measure of acidity and basicity respectively, since pH accounts for the concentration of H⁺ and pOH for the concentration of OH⁻ in a solution. In such a way, since the maximum scale is 14, we say that the addition between the pH and pOH must be 14:
[tex]pH+pOH=14[/tex]
Therefore, the correct answers are B. pOH = 14 - pH and D. pH = 14 - pOH since the both of them are derived from the previous definition.
Best regards.
Answer:
D: by subtracting the pOH from 14.
Explanation:
Akeem cut his finger during an investigation, and it is bleeding slightly. Before helping him bandage the wound,
which precaution should the teacher take?
O Tell someone to call 911,
O Put on protective gloves.
O Wash Akeem's finger in the shower.
O Apply disinfectant before cleaning.
Answer:
b.) Put on protective gloves
Answer:
2020 Put on protective gloves.
Explanation:
Can solid FeBr2 react with Cl2 gas to produce solid FeCl2 and Br2 gas? Why or why not?
Answer:
Yes
Explanation:
The balanced equation of the reaction is;
FeBr2 (aq) + Cl2 (g) → FeCl2 (aq) + Br2 (aq)
This reaction is possible because chlorine is more electronegative than bromine and can displace it from its salt.
In group seventeen, electro negativity decreases down the group. Hence as we move down the group, elements become less electronegative and can be displaced from their salt by more electronegative elements found earlier in the group.
Hence chlorine can displace bromine in FeBr2 to form FeCl2.
Answer:
Yes, because Cl2 has higher activity than Br2
Explanation:
Advantages of using a resource person in handling the first aid lesson
The advantage of a resource person would be that it will provide a hands-on activity that will allow the students to experience spacing between organs and on the body of the person.
It will also allow them to identify challenges when doing this and will engage them more in the activity and lesson.
Answer:A resource person add knowledge to the course
Explanation:
It would require ? Liters of water to dissolve 36 grams of the substance.
The correct answer is 3 liters
Explanation:
If a substance has a solubility of [tex]12 \frac{grams}{liter}[/tex], this means in 1 liter, the grams that can be dissolved are 12 grams. Now, considering Justin and Ellie need to dissolve 36 grams to calculate the number of liters just divide the total of grams into 12 as each liter dissolves only 12 grams. The process is shown below:
36 grams (the amount that will be dissolved) ÷ 12 (grames dissolved per liter) = 3 liters (liters to dissolved 36 grams)
Answer:
It would be 3 liters
Explanation:
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
If 11.2 g of naphthalene, C10H8, is dissolved in 107.8 g of chloroform, CHCl3, what is the molality of the solution
Answer:
CHC12
Explanation:
i am not really sure i am onna do a quick research 4 u tho
How many grams of sodium chloride are required to make 2.00 L of a solution with a concentration of 0.100 M?
Answer:
Mass = 11.688g
Explanation:
Volume = 2.00L
Molar concentration = 0.100M
Mass = ?
These quantities are relatted by the following equation;
Conc = Number of moles / volume
Number of moles = Conc * Volume = 2 * 0.100 = 0.2 mol
Number of moles = Mass / Molar mass
Mass = Number of moles * Molar mass
Mass = 0.2mol * 58.44g/mol
Mass = 11.688g
What is the value of the equilibrium constant, K, for a reaction for which ∆G° is equal to –5.20 kJ at 50°C?
Answer:
6.93
Explanation:
Step 1: Given data
Standard Gibbs free energy (∆G°): -5.20 kJTemperature (T): 50°CEquilibrium constant (K): ?Step 2: Convert the temperature to the Kelvin scale
We will use the following expression.
K = °C + 273.15
K = 50°C + 273.15
K = 323 K
Step 3: Calculate K
We will use the following expression.
∆G° = -R × T × ln K
-5.20 × 10³ J = -(8.314 J/mol.K) × 323 K × ln K
K = 6.93
g If the titration of a 10.0-mL sample of sulfuric acid requires 28.15 mL of 0.100 M sodium hydroxide, what is the molarity of the acid
Answer:
[tex]M_{acid}=0.141M[/tex]
Explanation:
Hello,
In this case, the reaction between sulfuric acid and hydroxide is:
[tex]H_2SO_4+2NaOH\rightarrow Na_2SO_4+2H_2O[/tex]
We can notice a 1:2 molar ratio between the acid and the base respectively, therefore, at the equivalence point we have:
[tex]2*n_{acid}=n_{base}[/tex]
And in terms of volumes and concentrations:
[tex]2*M_{acid}V_{acid}=M_{base}V_{base}[/tex]
So we compute the molarity of sulfuric acid as shown below:
[tex]M_{acid}=\frac{M_{base}V_{base}}{2*V_{acid}} =\frac{0.100M*28.15mL}{2*10.0mL}\\ \\M_{acid}=0.141M[/tex]
Best regards.
acid-catalyzed hydration of 1-methylcyclohexene gives two alcohols. The major product does not undergo oxidation, while the minor product will undergo oxidation. Explain
Answer:
Major product does not undergo oxidation since it is a tertiary alcohol whereas minor product undergoes oxidation to ketone as it is secondary alcohol.
Explanation:
Hello,
In this case, given the attached picture, the hydration of the 1 methylcyclohexene yields to alcohols; 1-methylcyclohexan-1-ol and 1-methylcyclohexan-2-ol. Thus, since the OH in the 1-methylcyclohexan-1-ol (major product) is bonded to a tertiary carbon (bonded with other three carbon atoms) it is not able to increase the number of oxygen bonds (oxidation) as it already attained the octet whereas the 1-methylcyclohexan-2-ol (minor product) is able to undergo oxidation to ketone as the carbon bonded to it is secondary (bonded with other two carbon atoms), so one extra bond the oxygen is allowed to be formed to carbonyl.
Best regards.
The enthalpy change for a chemical reaction is: a. the temperature change b. the amount of heat given off or absorbed c. related to molar volume d. none of the above
Answer:
b. the amount of heat given off or absorbed
Explanation:
Hello,
In this case, we should take into account a formal definition of enthalpy change such as an energetic change that occurs in a system when matter is transformed by a given chemical reaction from reactants to products. Thus, such energetic change is macroscopically exhibited and it is related with either a temperature increase or decrease; it means that if a reaction exhibits a temperature increase, we say that heat was given off and if the temperature exhibits a decrease, we say that heat is absorbed. For that reason, answer is b. the amount of heat given off or absorbed.
Regards.
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Compound has a molar mass of and the following composition: elementmass % carbon47.09% hydrogen6.59% chlorine46.33% Write the molecular formula of .
The given question is incomplete. The complete question is:
Compound X has a molar mass of 153.05 g/mol and the following composition:
element mass %
carbon 47.09%
hydrogen 6.59%
chlorine 46.33%
Write the molecular formula of X.
Answer: The molecular formula of X is [tex]C_6H_{10}Cl_2[/tex]
Explanation:
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mass of C= 47.09 g
Mass of H = 6.59 g
Mass of Cl = 46.33 g
Step 1 : convert given masses into moles.
Moles of C =[tex]\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{47.09g}{12g/mole}=3.92moles[/tex]
Moles of H =[tex]\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{6.59g}{1g/mole}=6.59moles[/tex]
Moles of Cl =[tex]\frac{\text{ given mass of Cl}}{\text{ molar mass of Cl}}= \frac{46.33g}{35.5g/mole}=1.30moles[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C = [tex]\frac{3.92}{1.30}=3[/tex]
For H = [tex]\frac{6.59}{1.30}=5[/tex]
For Cl =[tex]\frac{1.30}{1.30}=1[/tex]
The ratio of C : H: Cl= 3: 5 :1
Hence the empirical formula is [tex]C_3H_5Cl[/tex]
The empirical weight of [tex]C_3H_5Cl[/tex] = 3(12)+5(1)+1(35.5)= 76.5g.
The molecular weight = 153.05 g/mole
Now we have to calculate the molecular formula.
[tex]n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{153.05}{76.5}=2[/tex]
The molecular formula will be=[tex]2\times C_3H_5Cl=C_6H_{10}Cl_2[/tex]
