H.Chem- 70% Summative- Chemical Reactions Unit

A piece of zinc is placed in hydrochloric acid. Bubbles form on the surface of the metal. What are the products of the reaction?

Zn + 2HCl → ?

• ZnCl + H₂

• ZnCl₂ + H₂

• Zn + H₂Cl₂

• ZnH₂ + Cl₂

Tags

NGSS.HS-PS1-7

CHECK BOX ALL the choices that can serve as evidence that a chemical reaction has occurred?

• change in temperature

• production of gas

• change in density

• formation of a precipitate

• formation of an odor

What are the coefficients of the correctly balanced equation? ​ (a)   C₂H₆ + ​ (b)   O₂ → ​ (c)   H₂O + ​ (d)   CO₂

• 2
• 7
• 4
• 6
• 1
• 3
• 5

Tags

NGSS.HS-PS1-7

When aluminum pieces are placed in an aqueous solution of copper(II) chloride, a reaction occurs. Which of the following correctly describes the reaction and its products?

• Aluminum and copper(II) chloride form aluminum chloride and solid copper.

• Aluminum and copper(II) chloride form aluminum oxide and copper metal.

• Aluminum and copper(II) chloride form aluminum and copper metal only.

• No reaction occurs because copper is less reactive than aluminum.

Tags

NGSS.HS-PS1-7

Mathematical Equivalence

OFF

A chemical cold pack contains water and a solid salt such as ammonium nitrate. When the pack is activated, the salt dissolves in the water, and the pack becomes colder. Which type of energy change and reaction classification best describes what is happening?

• Exothermic process, similar to a combustion reaction

• Endothermic process, similar to reactions that absorb energy, such as decomposition

• Exothermic process, similar to a synthesis reaction

• Endothermic process, similar to reactions that release gas, such as single replacement

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What type of reaction is shown below? Zn + 2HCl → ZnCl₂ + H₂

• anionic single replacement

• synthesis

• double replacement

• cationic single replacement

Which of the following equations is a correct and balanced equation with a proper chemical reaction statement?

• 2Na + Cl₂ → 2NaCl which is a single replacement reaction

• 2Na + Cl₂ → NaCl₂

  which is a single replacement reaction

• Na + Cl₂ → 2NaCl

  which is a synthesis reaction

• 2Na + Cl₂ → 2NaCl which is a synthesis reaction

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

When hydrogen peroxide (H₂O₂) is poured onto a sample containing yeast, rapid bubbling occurs, and the container becomes warm. The yeast contains the enzyme catalase.

Which of the following correctly identifies both the products of this reaction and the best evidence that a chemical reaction has occurred?

• H₂ and O₂ are produced; evidence is color change

• H₂O and O₂ are produced; evidence is gas formation and temperature increase

• H₂O₂ and CO₂ are produced; evidence is precipitate formation

• H₂O and H₂ are produced; evidence is phase change

Will the following reaction occur? Pb + Ca(C₂H₃O₂)₂ → Ca + Pb(C₂H₃O₂)₂

• Yes, lead will replace calcium.

• Yes, acetates are always soluble.

• No, lead cannot replace calcium.

• No, lead will not react with acetate.