Question 1 If a solution contains 0.5 grams of NaCl and 100 grams of water, NaCl is the solute and water is the solvent.

A) True
B) False

Question 2
In a solution, the solute is the substance in the smaller amount.

A) True
B) False

Question 3
In a solution, the solvent is present in the larger amount.

A) True
B) False

Question 4
A solution is saturated when it contains the maximum amount of solute for the given solvent.

A) True
B) False

Question 5
Stirring a solution

A) increases the rate at which solute and solvent particles contact each other
B) makes more surface area available for the solvent to dissolve
C) prevents all the solute from being dissolved by the solvent

Question 6
Increasing the temperature of a solution will enable you to

A) dissolve more solute
B) remove the solvent
C) increase the surface area

Question 7
Which of the following is the best definition of a mixture?

A) compound of more than two types of elements
B) combination of two or more substances
C) a type of solid dissolved in a liquid

Explanation:

If a solution contains 0.5 grams of NaCl and 100 grams of water, NaCl is the solute and water is the solvent.

A) True

A solute is the substance that is dissolved in another medium which is the solvent. In this problem, the NaCl is the solute and the water is the solvent.

Question 2

In a solution, the solute is the substance in the smaller amount.

A) True

This is true. A solute is usually is lesser amount compared to the solvent.

Question 3

In a solution, the solvent is present in the larger amount.

A) True

The solvent is usually more in the solution. This is because during solvation, the solvent surrounds each particle of the solute and takes it into solution.

Question 4

A solution is saturated when it contains the maximum amount of solute for the given solvent.

A) True

A saturated solution is a solution in which no more solute can be dissolved further.

Question 5

Stirring a solution

A) increases the rate at which solute and solvent particles contact each other

Stirring increases the rate of solution by bringing the solute in contact with the solvent.

Question 6

Increasing the temperature of a solution will enable you to

A) dissolve more solute

The rate of dissolution increases by increase in temperature as the molecules gain more kinetic energy.

Question 7

Which of the following is the best definition of a mixture?  

B) combination of two or more substances

A mixture is a combination of two or more substances. The substances are not chemically combined together.

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol