Chemistry Regent - Jan 2015 Q41-50

Which two compounds are electrolytes? 

• KOH and CH₃COOH 
• KOH and C₅H₁₂
• CH₃OH and CH₃COOH
• CH₃OH and C₅H₁₂

 Which statement explains why a CO₂ molecule is nonpolar?

• Carbon and oxygen are both nonmetals.
• Carbon and oxygen have different electronegativities.
• The molecule has a symmetrical distribution of charge. 
• The molecule has an asymmetrical distribution of charge.

Which temperature change indicates an increase in the average kinetic energy of the molecules in a sample?

• 15°C to 298 K
•  37°C to 273 K
• 305 K to 0°C
• 355 K to 25°C

Which substance at STP can be represented by this particle diagram?

• N₂
• H₂
• Mg
• Kr

Which type of equilibrium exists in a sealed flask containing Br2(ℓ) and Br2(g) at 298 K and 1.0 atm? 

• static phase equilibrium
• static solution equilibrium
• dynamic phase equilibrium
• dynamic solution equilibrium

What are the products when potassium hydroxide reacts with hydrochloric acid?

• KH(s), Cl⁺(aq), and OH^-(aq) 
• K(s), Cl₂(g), and H₂O(ℓ)
• KCl(aq) and H₂O(ℓ)
• KOH(aq) and Cl₂(g)

 In a titration, 20.0 milliliters of a 0.150 M NaOH(aq) solution exactly neutralizes 24.0 milliliters of an HCl(aq) solution. What is the concentration of the HCl(aq) solution? 

• 0.125 M
• 0.180 M
• 0.250 M
• 0.360 M

What fraction of a Sr-90 sample remains unchanged after 87.3 years?

• 1/2
• 1/3
• 1/4
• 1/8

Which potential energy diagram represents the change in potential energy that occurs when a catalyst is added to a chemical reaction?

• 1
• 2
• 3
• 4

Which balanced equation represents a spontaneous radioactive decay?

• 1
• 2
• 3
• 4