Mixed Review Chemistry

A student has two dilute, colorless solutions, HCl(aq) and NaOH (aq) at the same temperature. Choose the correct ionic equation if the two solutions added together according to the below reaction.

HCl(aq) + NaOH(aq) --> NaCl(aq) + H2O(l)

• H+ (aq) + NaOH(aq) --> NaCl(aq) + H2O(l)

• HCl(aq) + OH- --> H2O(l)

• H+(aq) + OH-(aq) --> H2O(l)

• H+ (s) + OH-(s) --> H2O (l)

A Student mixes two dilute, colorless solutions, HCl(aq) and NaOH (aq) at the same temperature. Which of the following results would be evidence that a chemical reaction took place?

HCl(aq) + NaOH(aq) --> NaCl(aq) + H2O (l)

• The resulting solution is colorless

• The temperature of the mixture increases

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

• The temperature of the reaction mixture stays the same.

Tags

NGSS.HS-PS1-4

NGSS.HS-PS1-5

The half-reactions for the oxidation-reduction reaction between Zn_(s) and Cu²⁺_(aq) are represented below. Based on the half-reactions, what is the coefficient for Zn_(s) if the equation for the oxidation-reduction reaction is balanced with the smallest whole-number coefficients?

Zn_(s)→Zn²⁺_(aq) +2e⁻

Cu²⁺_(aq) +2e⁻→Cu_(s)

• 1

• 2

• 3

• 4

Tags

NGSS.HS-PS1-7

Consider the picture given and choose the correct

interpretation

• For every 1 mole of N₂ that reacts, 3 moles of H₂ are required and 2 moles of NH₃ are produced

• For every 2 moles of N₂ that reacts, 6 moles of H₂ are required and 6 moles of NH₃ are produced

• For every 2 moles of N₂ that reacts, 3 moles of H₂ are required and 2 moles of NH₃ are produced

• For every 1 mole of N₂ that reacts, 6 moles of H₂ are required and 2 moles of NH₃ are produced

Tags

NGSS.HS-PS1-2

 Which of the following describes the changes in forces of attraction that occur as water changes phase from a liquid to gas?

• H – O bonds break as H – H and O – O bonds form.

• Covalent bonds between water molecules are broken.

• Ionic bonds between H⁺ and OH^- ions are broken.

• Hydrogen bonds between water molecules are broken

Choose the right answer for the word ‘end-point’ in titration

• The end point is the point at which base/alkali is added

• The end point is the point at which indicator changes color

• The end point is the point at which indictor is added

• The end point is the point at which an acid is added

What are the oxidation numbers of the elements in sulfuric acid, H₂SO₄?

• H = +1

  S = +6

  O = -2

• H = + 1

  S = +4

  O = -2

• H = +2

  S = +1

  O = +4

• H = +2

  S = +6

  O = -8

HCl is dissolved in water as shown by the equation above. which of the following pairs includes the Brønsted-Lowry bases?

HCl(aq) + H2O (l) --> H3O+ (aq) + Cl-(aq)

• HCl (aq) and Cl- (aq)

• H2O (l) + Cl- (aq)

• H2O(l) + H3O+ (aq)

• HCl (aq) + H3O+ (aq)

Based on Arrhenius equation, which ion do all acids produce in aqueous solution?

• OH -

• H-

• O2-

• H+

A chemist working in a lab is trying to synthesize caffeine. In doing so, theoretically he can produce 50mg of caffeine. After the chemist finishes synthesizing the caffeine, he weighs it only to find out that 43mg are produced. What is the percent yield of caffeine in this synthesis process?

• 44%

• 97%

• 86%

• 36%