This question is incomplete, the complete question is;
A certain liquid X has a normal boiling point of 150.4 °C and a molar boiling point elevation constant kb is 0.60 °Ckgmol⁻¹.
A solution is prepared by dissolving some urea (NH22CO) in 750 g of X. This solution boils at 150.9 °C . Calculate the mass of urea that was dissolved. Round your answer to 3 significant digits.
Answer:
the mass of urea that was dissolved is 37.5 g
Explanation:
Given the data in the question;
normal boiling point of X; Tb⁰ = 150.4 °C
boiling point of solution Tb = 150.9 °C
Change in boiling point Δt = Tb - Tb⁰ = 150.9 °C - 150.4 °C = 0.5 °C
Kb = 0.6 °C.kg.mol⁻¹
V = 750 g
Now, we know that
Δt = Kb × molality
so
0.5 = 0.6 × molality
molality = 0.5 / 0.6
molality = 0.833
we know that molar mass of urea is 60 g/mol
so
molality = mass × 1000 / molar mass × volume( g )
we substitute
0.833 = ( mass × 1000 ) / ( 60 × 750 )
0.833 = ( mass × 1000 ) / 45000
0.833 × 45000 = mass × 1000
mass = ( 0.833 × 45000 ) / 1000
mass = 37485 / 1000
mass = 37.485 ≈ 37.5 g { 3 significance figure }
Therefore, the mass of urea that was dissolved is 37.5 g
Ice and water constitute a system:
A Chemically heterogeneous and physically heterogeneous
B Chemically homogeneous and physically heterogeneous
C Chemically homogeneous and physically homogeneous
D Chemically heterogeneous and physically homogeneous
E None of the above
Answer:
B
Explanation:
It's the same substance but in different states.
HETEROGENEOUS mixtures contain substances that are
not uniform in composition. The parts in the mixture can be separated by physical means.
4019K Express your answer as a nuclear equation.
Answer:
[tex]_{19} ^{40} K[/tex] → [tex]_{20} ^{40} Ca[/tex] + [tex]_{-1} ^{0} e[/tex] + ¯v
Explanation:
[tex]_{19} ^{40} K[/tex] is an unstable potassium isotope which has the capacity to undergo beta decay. During the decay process, it transforms to calcium atom with a release of beta particle and an antineutrino.
The required nuclear equation is:
[tex]_{19} ^{40} K[/tex] → [tex]_{20} ^{40} Ca[/tex] + [tex]_{-1} ^{0} e[/tex] + ¯v
The calcium formed due to this process is a stable atom.
What is the molecular formula of the structure below?
Picture is attached pls help I’ll mark as brainliest for the right answer
Answer:
C₆H₆
Explanation:
Each border of the figure represents 1 atom of carbon. We have 6 borders = 6 atoms of carbon.
Each atom of carbon form 4 bonds. All the carbons are doing a double bond and a single bond with other carbons. That means are bonded 3 times. The other bond (That is not represented in the figure. See the image) comes from hydrogens. As we have 6 carbons that are bonded each 1 with one hydrogen. There are six hydrogens and the molecular formula is:
C₆H₆This structure is: Benzene
Each of the following reactions were in equilibrium when the pressure of their containers was doubled. Chose which way the reaction shifted after the pressure change:
2NH3 (g)㈠No(g) +3H2(g) [Select ]
2Na3 PO4 (aq) + 3CaCl2 (aq) ㈠ Ca3 (PO4 )2 (s) + 6NaCl(aq) [Select ]
2C0(g)+O2 (g)->2CO2 (g) [Select ]
2H1(g) ㈠ H2(g) + 12(g) Neither
Answer:
Each of the following reactions was in equilibrium when the pressure of their containers was doubled. Chose which way the reaction shifted after the pressure change:
2NH3 (g)->N2(g) +3H2(g)
2Na3 PO4 (aq) + 3CaCl2 (aq) -> Ca3 (PO4 )2 (s) + 6NaCl(aq)
2CO(g)+O2 (g)->2CO2 (g)
2HI(g) -> H2(g) + I2(g)
Explanation:
Effect of pressure on equilibrium:
When pressure is increased on an equilibrium system,then equilibrium will shift in such a direction towards less number of moles of substrates.
For the first system,
2NH3 (g)->N2(g) +3H2(g)
increase in pressure,shifts the equilibrium towards the left side that is the formation of ammonia is favored.
For the second reaction:
2Na3 PO4 (aq) + 3CaCl2 (aq) -> Ca3 (PO4 )2 (s) + 6NaCl(aq)
The quilibrium will shift towards right.
Becuase right side less number of moles of substrates are there.
2CO(g)+O2 (g)->2CO2 (g)
For this system,the equilibrium will shift towards right side that is formation of CO2 gas is favored.
For the last system,
2HI(g) -> H2(g) + I2(g)
there is no effect of pressure.
Becuase the number of moles of substrates are same on both sides.
When we react a weak acid with a strong base of equal amounts and concentration, the component of the reaction that will have the greatest effect on the pH of the solution is: Select the correct answer below:_________
a. the reactant acid
b. the reactant base
c. the conjugate acid of the strong base
d. the conjugate base of the weak acid
Answer:
d. the conjugate base of the weak acid
Explanation:
The strong base (BOH) is completely dissociated in water:
BOH → B⁺ + OH⁻
The resulting conjugate acid (OH⁻) is a weak acid, so it remains in solution as OH⁻ ions.
By other hand, the weak acid (HA) is only slightly dissociated in water:
HA ⇄ H⁺ + A⁻
The resulting conjugate base (A⁻) is a weak base. Thus, it reacts with H⁺ ions from water to form HA, increasing the concentration of OH⁻ ions in the solution.
Therefore, the resulting solution will have a pH > 7 (basic).
Identify the options below that are results of adding a catalyst to a chemical system.
The reaction rates are increased.
The reaction quotient is unaffected.
The reaction quotient decreases.
The equilibrium constant is unaffected.
Answer:
The correct options are a, b and d
Explanation:
A catalyst is a substance that increases the rate of a chemical reaction by reducing the activation energy. Le Catelier's principle explains how a substance or an "action" can affect a reaction in equilibrium.
The principle states that when a change is made to the conditions of a reacting system at equilibrium, the position of the equilibrium moves to counteract the change made. These changes are change in temperature, pressure, volume and/or concentration. These changes will either cause the equilibrium to shift forward or backward.
However, the presence of a catalyst DOES NOT affect a chemical equilibrium/equilibrium constant nor does it affect the reaction quotient because the same amount of reactants and products are available just as in uncatalyzed reaction except that the reaction proceeds faster (which does not affect equilibrium).
The rate of reaction is given as the time required by the reactant to convert into the product. The addition of catalyst increases the rate of reaction, while the reaction quotient and the equilibrium remain unaffected.
What is a catalyst?A catalyst is a chemical or compound that adds to the reaction and lowers the activation energy by providing an alternative path to the reaction.
The catalyst takes part in the reaction but did not consume in the chemical reaction.
The equilibrium and the reaction quotient are dependent on the conversion of the reactant to the product. The catalyst is not used in the reaction and thus did not affect the reaction quotient or the equilibrium.
Hence, options A, B, and D are correct for the use of catalysts in the chemical reaction.
Learn more about catalysts, here:
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The largest population that an environment can support is called _____.
A) birth capacity
B) death factor
C)limiting factor
D) carrying capacity
Answer:
D) caring capacity
Explanation:
The largest population that an environment can support is called its carrying capacity.hope it helps.stay safe healthy and happy.Answer:
D)
Explanation:
The largest population that an environment can support is by definition a carrying capacity
Voltages listed in textbooks and handbooks are given as standard cell potentials (voltages). What is meant by a standard cell?
Answer:
Find the definition below.
Explanation:
A standard cell is a group of transistors that have a regular electromotive force flowing through them. They follow either the boolean function or the storage function. A technology library that is made up of a collection of standard cells can be used to facilitate the placement, routing, and synthesis of the Application-specific Integrated Circuit (ASIC).
Electronic Design Automation is an example of an apparatus that implements this functionality.
Na2CO3 reacts with dil.HCl to produce NaCl, H2O and CO2. If 21.2 g of pure Na2CO3 are added in a solution containing 21.9g HCl , a. Find the limiting reagent. (2) b. Calculate the number of moles of excess reagent left over.(2) c. Calculate the number of molecules of H2O formed.(1) d. Calculate volume of CO2 gas produced at 270C and 760mm Hg pressure.(2) e. Write significance of limiting reagent
Answer:
See explanation
Explanation:
Equation of the reaction;
Na2CO3(aq) + 2HCl(aq) -------> 2NaCl(aq) + H2O(l) + CO2(g)
Number of moles of Na2CO3 = 21.2g/106g/mol = 0.2 moles Na2CO3
Number of moles of HCl = 21.9g/36.5g/mol = 0.6 moles of HCl
1 mole of Na2CO3 reacts with 2 moles of HCl
0.2 moles of Na2CO3 reacts with 0.2 × 2/1 = 0.4 moles of HCl
Hence Na2CO3 is the limiting reactant
Since there is 0.6 moles of HCl present, the number of moles of excess reagent=
0.6 moles - 0.4 moles = 0.2 moles of HCl
1 mole of Na2CO3 forms 1 mole of water
0.2 moles of Na2CO3 forms 0.2 moles of water
Number of molecules of water formed = 0.2 moles × 6.02 × 10^23 = 1.2 × 10^23 molecules of water
1 mole of Na2CO3 yields 1 mole of CO2
0.2 moles of Na2CO3 yields 0.2 moles of CO2
1 mole of CO2 occupies 22.4 L
0.2 moles of CO2 occupies 0.2 × 22.4 = 4.48 L at STP
Hence;
V1=4.48 L
T1 = 273 K
P1= 760 mmHg
T2 = 27°C + 273 = 300 K
P2 = 760 mmHg
V2 =
P1V1/T1 = P2V2/T2
P1V1T2 = P2V2T1
V2 = P1V1T2/P2T1
V2 = 760 × 4.48 × 300/760 × 273
V2= 4.9 L
The limiting reactant is the reactant that determines the amount of product formed in a reaction. When the limiting reactant is exhausted, the reaction stops.
Which group has one valence electron
Answer:
Alkaline earth metals or akali metals
The chemical formula for hydrogen chloride is HCl A chemist determined by measurements that moles of hydrogen chloride participate in a chemical reaction. Calculate the mass of hydrogen chloride that participates. Be sure your answer has the correct number of significant digits.
The question is incomplete, the complete question is;
. A chemist determined by measurements that 0.015 moles of hydrogen chloride participate in a chemical reaction. Calculate the mass of hydrogen chloride that participates Round your answer to 2 significant digits. x S. ?
Answer:
0.54 g
Explanation:
Recall that;
Number of moles = mass/molar mass
Molar mass of HCl =36.5 g/mol
Mass= number of moles × molar mass
Mass= 0.015 moles × 36 g/mol
Mass= 0.54 g
Identify the most oxidized compound. Group of answer choices CH3CH2CHO CH3CH2CH3 CH3CH2CH2OH CH3CH2OCH3 CH3CH2COOH
Answer:
Huh!?
Explanation:
explain me please
A chemist fills a reaction vessel with 9.47 atm nitrogen monoxide (NO) gas, 2.61 atm chlorine (C12) gas, and 8.64 atm nitrosyl chloride (NOCI) gas at a temperature of 25.0°C. Under these conditions, calculate the reaction free energy AG for the following chemical reaction:
2NO(g) + Cl2(g) = 2NOCI (g)
Use the thermodynamic information in the ALEKS Data tab. Round your answer to the nearest kilojoule.
Answer: The Gibbs free energy change of the reaction is 2.832 kJ.
Explanation:
The relationship between Gibbs free energy change and reaction quotient of the reaction is:
[tex]\Delta G^o=-RT\ln Q_p[/tex]
where,
[tex]\Delta G^o[/tex] = Gibbs free energy change
R = Gas constant = 8.314 J/mol.K
T = temperature = [tex]25^oC=298K[/tex]
[tex]Q_p[/tex] = reaction quotient = [tex]\frac{p_{NOCl}^2}{(p_{NO}^2)\times (p_{Cl_2})}[/tex]
We are given:
[tex]p_{NOCl}=8.64atm\\p_{NO}=9.47atm\\p_{Cl_2}=2.61atm[/tex]
Putting values in above equation, we get:
[tex]\Delta G^o=-(8.314)\times 298K\times \ln (\frac{(8.64)^2}{(9.47)^2\times (2.61)})\\\\\Delta G^o=-8.314\times 298\times (-1.143)[/tex]
[tex]\Delta G^o=2831.86J=2.832kJ[/tex] (Conversion factor: 1 kJ = 1000 J)
Hence, the Gibbs free energy change of the reaction is 2.832 kJ.
What is the name of this molecule?
Explanation:
here is your answer
hope this will help you
Methanoic acid is the simplest carboxylic acid molecule. It has one carbon atom. Draw the structural model for methanoic acid (using C and H).
ANSWER IS ABOVE
THE METHANOIC ACID
The blank is the accepted form of gathering and reporting information within the science community.
Answer:
Scientific method.
Explanation:
Scientific method is the way taken to acquire scientific knowledge. It includes experiments, statistical analysis of existing data, and all kinds of observations of the world around us, while theoretical research is based on deriving certain theories about the world from basic principles, in a mathematical or logical way. The scientific method applies to both types of research, and emphasizes that scientific research is objective, that it can be verified by other scientists, and that knowledge is not acquired without context, but in a way that leads to a greater understanding of previous research and the world. we live in. To contribute to this, researchers are expected to clearly record both their findings and the methods they use to arrive at the results.
All of the orbitals in the 3d subshell have a principal quantum number value of 3, an angular momentum quantum number of:_____.
Answer:
According to the four quantum numbers; magnetic quantum number is the same as angular momentum quantum number. so the answer is 5
Explanation:
for d subshell angular momentum "d" is assigned a value of : m= 2(range from negative to positive i.e, -2 to 2) so we have [ -2, -1 ,0, 1 , 2] which concludes to 5.
What is unit? Write down the units of mass, temperature and power
Explanation:
a single thing, person, or group forming part of a whole There are 36 units in my apartment building. the least whole number : one. a fixed quantity (as of length, time, or value) used as a standard of measurement An inch is a unit of length.mass=kilogram (kg)
temperature=kelvin
power=watt
hope it helps
stay safe healthy and happy..Many reactions involve a change in hybridization of one or more atoms in the starting material. In this reaction, determine the hybridization of the indicated atoms in the organic starting material, and determine if they have changed hybridization during the reaction.
Answer:
Please find the complete question and its solution file in the attachment.
Explanation:
The metal tantalum becomes superconducting at temperatures below 4.483 K. Calculate the temperature at which tantalum becomes superconducting in degrees Celsius.
Answer:
The correct answer is "-268.667°C".
Explanation:
Given:
Temperature,
= 4.483 K (below)
Now,
The formula of temperature conversion will be:
⇒ [tex]T(^{\circ} C)=T(K)-273.15[/tex]
By putting the values, we get
⇒ [tex]=4.483-273.15[/tex]
⇒ [tex]=-268.667^{\circ} C[/tex]
Thus the above is the correct answer.
How many carbon atoms are there in 15 lbs of sugar, C12H22O11?
Answer:
A molecule of sucrose (C12H22O11) has 12 carbon atoms, 22 hydrogen atoms and 11 oxygen atoms.
Explanation:
if this does not help let me know :)
There are 1.4376 × 10²⁶ carbon atoms in 15 lbs of sugar (C12H22O11).
From the given information,
Using the standard conversion method;
1 lbs = 453.592 gram
∴
15 lbs = (453.592 gram × 15 lbs/1 lbs)
= 6803.88 grams
Now, we will need to determine the molar mass of the sugar compound C12H22O11.
Molar mass of C12H22O11 = (12 × 12) +(1 × 22) + (16 × 11)
Molar mass of C12H22O11 = 144 + 22 + 176
Molar mass of C12H22O11 = 342 g/mol
Using the relation:
[tex]\mathbf{Number \ of \ moles = \dfrac{mass}{molar \ mass}}[/tex]
Number of moles = [tex]\dfrac{6803.88 }{ 342}[/tex]
Number of moles of C12H22O11 = 19.894 moles
Since we've known the number of moles present in C12H22O11, the next thing to do is determine the number of molecules of sugar by using Avogadro's constant:
i.e.
number of moles of sugar = [tex]19.894 moles \times \dfrac{6.023 \times 10^{23}}{mol}[/tex]
= 1.198 × 10²⁵ molecules of C12H22O11
Now to determine the number of carbon atoms in 15 lbs, we have:
= number of carbon atoms × amount of molecules
= 12 × 1.198 × 10²⁵ carbon atoms
= 1.4376 × 10²⁶ carbon atoms
Therefore, we can conclude that there are 1.4376 × 10²⁶ carbon atoms present in 15 lbs of sugar, C12H22O11
Learn more about atoms here:
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What is the mass of 2.30x10^22 formula units of NaOH (molar mass =40.0g/mol)
Answer:
643(%=:(¥75 )(:7$"8"),"7$"()9_/"¥?:
The N H 2 group makes the molecule an amine. Like alcohols, amines can participate in hydrogen bonding. If the drawn molecule encounters water molecules, there will be (select all that apply): a hydrogen bond between the hydrogen of water and the carbon of the amine. a hydrogen bond between the hydrogen of water and the nitrogen of the amine. a hydrogen bond between the oxygen of water and a hydrogen from the -NH2 group. a hydrogen bond between the oxygen of water and a hydrogen from the -CH3 group. no hydrogen bonds.
Answer:
a hydrogen bond between the hydrogen of water and the nitrogen of the amine
a hydrogen bond between the oxygen of water and a hydrogen from the -NH2 group
Explanation:
A hydrogen bond is formed between molecules in which hydrogen is bonded to a highly electronegative element.
In amines, hydrogen is bonded to nitrogen while in water, hydrogen is bonded to oxygen. Both are highly electronegative elements hence hydrogen bonding is possible between amines and water.
This hydrogen bond may involve;
The hydrogen of water and the nitrogen of the amine
Or
The oxygen of water and a hydrogen from the -NH2 group
A sample of 10.6 g of KNO3 was dissolved in 251.0 g of water at 25 oC in a calorimeter. The final temperature of the solution was 21.5 oC. What is the molar heat of solution of KNO3
Answer:
36.55kJ/mol
Explanation:
The heat of solution is the change in heat when the KNO3 dissolves in water:
KNO3(aq) → K+(aq) + NO3-(aq)
As the temperature decreases, the reaction is endothermic and the molar heat of solution is positive.
To solve the molar heat we need to find the moles of KNO3 dissolved and the change in heat as follows:
Moles KNO3 -Molar mass: 101.1032g/mol-
10.6g * (1mol/101.1032g) = 0.1048 moles KNO3
Change in heat:
q = m*S*ΔT
Where q is heat in J,
m is the mass of the solution: 10.6g + 251.0g = 261.6g
S is specififc heat of solution: 4.184J/g°C -Assuming is the same than pure water-
And ΔT is change in temperature: 25°C - 21.5°C = 3.5°C
q = 261.6g*4.184J/g°C*3.5°C
q = 3830.87J
Molar heat of solution:
3830.87J/0.1048 moles KNO3 =
36554J/mol =
36.55kJ/mol
Consider the balanced chemical equation below.
3 A ⟶ C + 4 D
How many moles of C would be produced if 7 moles of A were used?
Answer:
2.33 mol C
Explanation:
Step 1: Write the balanced generic chemical equation
3 A ⟶ C + 4 D
Step 2: Establish the appropriate molar ratio
According to the balanced equation, the molar ratio of A to C is 3:1.
Step 3: Calculate the number of moles of C produced from 7 moles of A
We will use the previously established molar ratio.
7 mol A × 1 mol C/3 mol A = 2.33 mol C
What is the law of multiple proportions?
A. The proportion of elements to compounds is constant.
B. All elements are found in equal proportions in nature.
C. Different compounds may contain the same elements but may have different ratios of those elements.
D. All compounds contain the same elements in the same proportions.
Answer:
a. the proportion of elements to compounds is constant.
a sample of copper was heated at 275.1 C and placed into 272 g of water at 21.0 C. The temperature of the water rose at 29.7 C. How many grams of copper were in the sample
Answer:
104.8 g
Explanation:
From the question given above, the following data were obtained:
Initial temperature of copper (T꜀) = 275.1 °C
Mass of water (Mᵥᵥ) = 272 g
Initial temperature of water (Tᵥᵥ) = 21 °C
Equilibrium temperature (Tₑ) = 29.7 °C
Mass of copper (M꜀) =?
NOTE:
Specific heat capacity of copper (C꜀) = 0.385 J/gºC
Specific heat capacity of water (Cᵥᵥ) = 4.184 J/gºC
Finally, we shall determine the mass of the copper in the sample. This can be obtained as follow:
Heat loss by copper = Heat gained by water
M꜀C꜀(T꜀ – Tₑ) = MᵥᵥCᵥᵥ(Tₑ – Tᵥᵥ)
M꜀ × 0.385 (275.1 – 29.7) = 272 × 4.184(29.7 – 21)
M꜀ × 0.385 × 245.4 = 1138.048 × 8.7
M꜀ × 94.479 = 9901.0176
Divide both side by 94.479
M꜀ = 9901.0176 / 94.479
M꜀ = 104.8 g
Thus, the mass of the copper in the sample is 104.8 g
Indicate how the concentration of each species in the chemical equation will change to reestablish equilibrium after reactant or product is added.
2CO(g) + O2(g) ⇌ 2CO2
Answer:
Indicate how the concentration of each species in the chemical equation will change to reestablish equilibrium after reactant or product is added.
[tex]2CO(g) + O2(g) <=> 2CO2[/tex]
Explanation:
When the reactants concentration increases, then the equilibrium will shift towards products and when the concentration of products increases, then equilibrium will shift towards reactants.
So, increases in concentration of carbon monoxide (CO) shifts the equilibrium to favor the formation of carbondioxide.
Similarly increase in concentration of oxygen also favor the formation of product carbon dioxide.
Increase in concentration of CO2 favors the formation of CO and O2.
Decrease in product concentration also favors the formation of product.
Decrease in reactant concentration favors the formation of reactants only.
The element least likely to obey the octet rule in forming chemical bonds is Group of answer choices oxygen. carbon. nitrogen. neon. fluorine.
Answer:
neon
Explanation:
The octet rule states that atoms of elements are stable when they possess 8 electrons on their outermost shell.
Hence, atoms of elements participate in chemical reactions in order to attain this octet structure (eight electrons in the outermost shell).
Neon is a noble gas and already has eight electrons in its outermost shell. Hence, neon is least likely to obey the octet rule.
Which one of the following is an example of a balanced chemical reaction?
a. 8HCl + 2KMnO4 → 3Cl2 + 2MnO2 + 4H2O + 2KCl.
b. 6HCl + 2KMnO4 → 2Cl2 + 2MnO2 + 4H2O + 2KCl.
c. 2HCl + 2KMnO4 → Cl2 + MnO2 + 2H2O + 2KCl.
d. HCl + KMnO4 → Cl2 + MnO2 + H2O + KCl.
e. HCl + KMnO4 → Cl2 + MnO2 + 2H2O + KCl.
Answer:
Option a.
Explanation:
To determine which is a balanced chemical reaction, see the stoichiometry.
Stoichiometry coefficients are the numbers that appear before the compounds. These numbers indicate moles of substance.
Notice that the number of elements must be the same in both sides of the equation.
In this case, option a is the balanced chemical reaction.
8HCl + 2KMnO₄ → 3Cl₂ + 2MnO₂ + 4H₂O + 2KCl
8 moles of HCl react to 2 moles of potassium permanganate in order to produce 2 moles of magnessium dioxide, 3 moles of chlorine, 2 moles of potassium chloride and 4 moles of water.
8 H, 8 Cl, 2 K, 2 Mn and 8 O
