SC 7 N 1 4

How does a balanced chemical equation satisfy the Law of Conservation of Mass?

• during a chemical reaction, the total amount of matter stays the same

• during a chemical reaction, matter is destroyed

• during a chemical reaction, one or more new substances are formed

• during a chemical reaction, the total number of atoms increases

Tags

NGSS.MS-PS1-5

Substance A has a mass of 11 grams. When Substance A was mixed with Substance B, a new substance was formed. Which statement BEST describes the Law of Conservation of Mass?

• the mass of substance B is equal to the mass of the product

• the mass of the product is equal to the mass of the reactant

• the mass of the product is less than the mass of the reactant

• the mass of substance A and B is less than the mass of the product

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Which is true of a chemical equation?

• products and reactants must be balanced

• subscripts must be used with all products and reactants

• energy must be included in the beginning of a reaction

• coefficients must be used with all products and reactants

Tags

NGSS.MS-PS1-5

Two substances react and the mass is recorded. The mass of the products does not equal the mass of the reactants. Which is the BEST reason for the difference in the masses?

• the scale was not balanced

• some of the mixture spilled

• gas was produced and lost to the environment

• substances were added after the initial mass was recorded

Tags

NGSS.MS-PS1-5

Which BEST represents a balanced equation?

• HgO --> Hg + O₂

• 2Fe + O₂ --> Fe₂O₃

• 2H₂ + O₂ --> 2H₂O

Tags

NGSS.MS-PS1-5

A 14 g sample of Mg reacts with a 12 g sample of S when heated. What mass of MgS is MOST LIKELY produced?

• 2 grams

• 20 grams

• 26 grams

• 168 grams

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Which BEST explains why the equation below is NOT balanced? 2Na + H₂O ----> 2NaOH + H₂

• there is too much sodium in the reactants

• there is not enough water in the reactants

• there is too much hydrogen gas in the products

• there is not enough sodium hydroxide in the products

Tags

NGSS.MS-PS1-5

One molecule of CO₂ combines with one molecule of H₂O to make one molecule of carbonic acid. According to the Law of Conservation of Mass, how many atoms of carbon should be in the carbonic acid?

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-1

Which pair is conserved during a chemical reaction?

• molecules and volume

• atoms and molecules

• volume and mass

• mass and atoms

Tags

NGSS.MS-PS1-5

When 18 grams of zinc are combined with 20 grams of hydrochloric acid, 2 new products form. What will be the combined mass of the products?

• 2 grams

• 38 grams

• 40 grams

• 80 grams

Tags

NGSS.MS-PS1-5