Unit 4 Review

HCl(aq) + NaOH(aq) → NaCl(aq) + H₂O(l)

A student had two dilute, colorless solutions, HCl(aq) and NaOH(aq), which were at the same temperature. The student combined the solutions, and the reaction represented above occurred. Which of the following results would be evidence that a chemical reaction took place?

• The resulting solution is colorless.

• The temperature of the reaction mixture increases.

• The total volume of the mixture is approximately equal to the sum of the initial volumes.

• The resulting solution conducts electricity.

Tags

NGSS.HS-PS1-7

NGSS.HS-PS1-4

NGSS.HS-PS1-5

If one clear colorless liquid is mixed with a clear red liquid, which of the following would occur if it is physical change?

• a cloudy liquid shows after the substances are mixed

• the mixture is a light red in color

• the temperature of the mixture increased

• the mixture bubbled after 10 seconds

Equal volumes of 0.2M solutions of lead(II) nitrate and potassium bromide are combined to form lead(II) bromide as a yellow precipitate. Which of the following is the correct net ionic equation for the reaction?

• Pb²⁺(aq) + 2Br⁻(aq) → PbBr₂(s)

• K⁺(aq) + NO₃⁻(aq)→ KNO₃(aq)

• Pb²⁺(aq) + 2NO₃⁻(aq) + 2K⁺(aq) + 2Br⁻(aq) → 2K⁺(aq) + 2NO₃⁻(aq) + PbBr₂(s)

• Pb(NO₃)₂(aq) + 2KBr(aq) → PbBr₂(s) + 2KNO₃(aq)

Tags

NGSS.HS-PS1-7

NGSS.HS-PS1-2

A mixture of CO(g) and O₂(g) is placed in a container, as shown above. A reaction occurs, forming CO₂(g). Which of the following best represents the contents of the box after the reaction has proceeded as completely as possible.

• 
• 
• 
• 

Tags

NGSS.HS-PS1-7

NGSS.HS-PS1-2

A student places a sample of a pure metal in a crucible and heats it strongly in air. Data from the experiment are given in the table above. The final mass was determined after the sample was cooled to room temperature. Which of the following statements related to the experiment is correct?

• The mass of the sample decreased, so physical changes occurred as the metal first melted and then boiled out of the crucible.

• The mass of the sample increased, so a chemical change occurred when bonds formed between the metal and another substance.

• There was nothing for the metal to react with, so only a physical change could have occurred.

• The sample was only heated, so neither a physical nor a chemical change occurred.

Tags

NGSS.HS-PS1-7

NGSS.HS-PS1-2

NGSS.HS-PS1-4

C₃H₈(g) + 4 Cl₂(g) → C₃H₄Cl₄(g) + 4 HCl(g)

A 6.0 mol sample of C₃H₈(g) and a 20. mol sample of Cl₂(g) are placed in a previously evacuated vessel, where they react according to the equation above. After one of the reactants has been totally consumed, how many moles of HCl(g) have been produced?

• 4.0 mol

• 8.0 mol

• 20. mol

• 24 mol

Tags

NGSS.HS-PS1-7

Al(s) → Al³⁺(aq) + 3e−

Zn²⁺(aq) + 2e− → Zn(s)

The half-reactions for the oxidation-reduction reaction between Al(s) and Zn²⁺(aq) are represented above. Based on the half-reactions, what is the coefficient for Al(s) if the equation for the oxidation-reduction reaction is balanced with the smallest whole-number coefficients?

• 1

• 2

• 3

• 4

Tags

NGSS.HS-PS1-7

Read the burette.

• 3.50 mL

• 3.60 mL

• 4.40 mL

• 4.50 mL

What is the charge of manganese in potassium permanganate? (KMnO₄)

• +2

• +4

• +5

• +7

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-1

When 44.0 grams of propane (C₃H₈ molar mass = 44.0 g/mol) undergoes complete combustion, how many grams of water will be produced?

C₃H₈ + 5 O₂ --> 3 CO₂ + 4 H₂O

• 18.0 g

• 72.0 g

• 9.0 g

• 36.0 g