Deck 3: Chemical Reactions, Water and Solutions

Question 1

Highway road crews sometimes spread salt on icy roads during the winter because the solution process generates heat, which melts the ice.

Answer 1

False

Question 2

The following aqueous solutions, with one mole of each solid in equal volumes of water are prepared.
C₆H₁₂O_6(s) $\rightarrow$ C₆H₁₂O_6(aq)
NaNO_3(s) $\rightarrow$ Na⁺_(aq) + NO₃^-_(aq)
CaCl_{2 (aq)} $\rightarrow$ Ca²⁺_(aq) + 2Cl^-_(aq)
Which solution would have the lowest freezing point?

A) C₆H₁₂O₆
B) NaNO₃
C) CaCl₂
D) All of the responses would have the same freezing point.

Answer 2

CaCl₂

Question 3

One mole of particles lowers the freezing point of 1,000 g of water by 1.76ºC. What is the freezing point of a solution containing one mole of NaNO₃ in 1,000 g of water?

A) 30.24ºC
B) 28.48ºC
C) ?1.76ºC
D) ?3.52ºC

Answer 3

?3.52ºC

Question 4

What is the number of atoms on each side of the equation, CH₄ + 2O₂ $\rightarrow$ CO₂ + 2H₂O?

A) 5
B) 6
C) 7
D) 9

Question 5

What is the total mass of products in the methane reaction CH₄ + 2O₂ $\rightarrow$ CO₂ + 2H₂O?

A) 80 u
B) 64 u
C) 62 u
D) 48 u

Question 6

What is the mass percent of sodium in washing soda, Na₂CO₃?

A) 43.4%
B) 32.5%
C) 21.7%
D) 62.1%

Question 7

How many molecules are in an 8.0 g sample of oxygen gas, O₂?

A) 6.0 × 10²³
B) 3.0 × 10²³
C) 1.5 × 10²³
D) 12.0 × 10²³