1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
elena55 [62]
2 years ago
7

An aqueous KNO3 solution is made using 72.5 g of KNO3 diluted to a total solution volume of 2.00 L. Calculate the molarity, mola

lity, and mass percent of the solution. (Assume the density of 1.05 g/mL for the solution.)
Chemistry
1 answer:
Sonja [21]2 years ago
3 0

Answer:

The molarity is 0.359\frac{moles}{L}

The molality is 0.354 \frac{moles}{kg}

The mass percent of the solution es 3.45%

Explanation:

Molarity is a unit of concentration that indicates the amount of moles of solute that appear dissolved in each liter of the mixture. It is determined by:

Molarity (M)=\frac{number of moles of solute}{volume}

Being:

  • K: 39 g/mole
  • N: 14 g/mole
  • O: 16 g/mole

The molar mass of KNO₃ is:

KNO₃=  39 g/mole + 14 g/mole + 3*16 g/mole= 101 g/mole

You can apply the following rule of three: if 101 grams of KNO₃ are present in 1 mole, 72.5 grams in how many moles are present?

moles of KNO_{3}=\frac{72.5 grams*1 mole}{101 grams}

moles of KNO₃= 0.718

So you have:

  • moles of KNO₃= 0.718
  • volume= 2 L

Applying this quantity in the definition of molarity:

molarity=\frac{0.718 moles}{2 L}

Molarity= 0.359\frac{moles}{L}

<u><em>The molarity is 0.359</em></u>\frac{moles}{L}<u><em></em></u>

Molality is a way of measuring the concentration of solute in solvent and indicates the amount of moles of solute in each kilogram of solvent.

Then the molality is calculated by:

Molality=\frac{moles of solute}{mass of solvent in kilograms}

Density is defined as the property that matter, whether solid, liquid or gas, has to compress in a given space. That is, it is the amount of mass per unit volume. So, if the density of 1.05 g / mL for the solution indicates that in 1 mL of solution there are 1.05 grams of solution, in 2000 mL (where 2L = 2000 mL, because 1 L = 1000mL) how much mass is there?

mass=\frac{2000 mL*1.05 grams}{1 mL}

mass= 2100 grams

Since mass solution = mass water + mass KNO₃

then mass water = mass solution - mass KNO₃

Being mass solution 2100 grams and mass KNO₃ 72.5 grams, and replacing you get: mass water= 2100 grams - 72.5 grams

mass water= 2,027.5 grams

Then, being:

  • moles of KNO₃= 0.718
  • mass of solvent in kilograms= 2.0275 kg (being 2,027.5 grams= 2.0275 kilograms because 1,000 grams= 1 kilogram)

Replacing in the definition of molality:

molality=\frac{0.718 moles}{2.0275 kg}

molality= 0.354 \frac{moles}{kg}

<u><em>The molality is 0.354 </em></u>\frac{moles}{kg}<u><em></em></u>

The mass percent of a solution is the number of grams of solute per 100 grams of solution. Then the mass percent is the mass of the element or solute divided by the mass of the compound or solute and the result of which is multiplied by 100 to give a percentage.

mass percent=\frac{mass of solute}{mass of solution} *100

So, in this case:

mass percent=\frac{72.5 grams}{2100 grams} *100

mass percent= 3.45 % KNO₃ by mass

<u><em>The mass percent of the solution es 3.45%</em></u>

You might be interested in
Prove that PV = nRT.​
qaws [65]

Find your answer in the explanation below.

Explanation:

PV = nRT is called the ideal gas equation and its a combination of 3 laws; Charles' law, Boyle's law and Avogadro's law.

According to Boyle's law, at constant temperature, the volume of a gas is inversely proportional to the pressure. i.e V = 1/P

From, Charles' law, we have that volume is directly proportional to the absolute temperature of the gas at constant pressure. i.e V = T

Avogadro's law finally states that equal volume of all gases at the same temperature and pressure contain the same number of molecules. i.e V = n

Combining the 3 Laws together i.e equating volume in all 3 laws, we have

V = nT/P,

V = constant nT/P

(constant = general gas constant = R)

V = RnT/P

by bringing P to the LHS, we have,

PV = nRT.

Q.E.D

6 0
2 years ago
Elements
Snezhnost [94]

Answer:

elements are composed of

electrons with a little mass and negative charge

protons with mass and positive charge

neutrons with mass and no charge

isotopes same number of protons, different in neutrons

share me the other part of the photo to complete!!!

7 0
3 years ago
If 72.5 grams of calcium metal (Ca) react with 65.0 grams of oxygen gas (O2) in a synthesis reaction, how many grams of the exce
Natali5045456 [20]
2Ca + O2 = 2CaO
First, determine which is the excess reactant
72.5 g Ca (1 mol) =1.8089725036
(40.078 g)

65 g O2 (1 mol) =2.0313769611
(15.999g × 2)
Since the ratio of to O2 is 2:1 in the balanced reaction, divide Ca's molar mass by 2 to get 0.9044862518. this isn't necessary because Ca is already obviously the limiting reactant. therefore, O2 is the excess reactant.

Now do the stoichiometry
72.5 g Ca (1 mol Ca) (1 mol O2)
(40.078 g Ca)(2 mol Ca)(31.998g O2)

=0.0282669621 g of O2 left over
5 0
3 years ago
Which headings should be used to complete this table?
ch4aika [34]

Answer:functional group (top row); sources in nature (bottom row)

Explanation:

6 0
2 years ago
Read 2 more answers
Are these radiation, conduction, or convection?
irakobra [83]
Hey! 1) Convection [Warm water is less dense, so it rises.] 2) Conduction [The metal skewer is heated by the fire, and it is directly touching your hand. The metal skewer transfers heat to your hand through conduction.] 3) Conduction [The rock is directly touching you, so it transfers heat to you through conduction.] 4) Convection [Convection causes weather systems because hot air sinks and cold air sinks] 5) Convection [The hot air rises because it is less dense while the cold air sinks because it is denser.] ~Hope this helped~
3 0
2 years ago
Other questions:
  • Which statement is true for a cooling curve?
    9·2 answers
  • The products
    7·1 answer
  • What is the name for a substance formed in a chemical reaction?
    14·1 answer
  • What does conserving mass mean in a chemical equation?
    5·2 answers
  • Write a balanced half-reaction for the oxidation of gaseous nitric oxide to aqueous nitrous acid in acidic aqueous solution. Be
    8·1 answer
  • Atorvastatin is sold under the trade name Lipitor and is used for lowering cholesterol. Annual global sales of this compound exc
    6·1 answer
  • CHEMISTRY HELP<br> Once the following equation is balanced, what is the correct coefficient for Z₂?
    15·1 answer
  • R equals The formula for Ohm's law can be written: R equals _____. I / V V / I I x V
    8·1 answer
  • When salt dissolves in water:
    7·1 answer
  • Why does nobody fking answer my questions.
    5·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!