Chemical Change and Law of Conservation of Mass

One reactant, with a mass of 7 grams (g), is combined with another reactant, with a mass of 3 g, in a sealed container. After the reaction, what is the most reasonable prediction for the total mass of the products of this reaction?

• 7g

• 3g

• 10g

• 4g

Tags

NGSS.MS-PS1-5

In a sealed container, Sarah combines a reactant with a mass of 20 grams with another reactant with a mass of 16 grams. After the reaction, what is the most reasonable prediction Sarah can make for the total mass of the products of this reaction?

• 26g

• 4g

• 8g

• 36g

Tags

NGSS.MS-PS1-5

According to the law of conservation of mass, mass is neither created nor destroyed in any ordinary chemical reaction. Which of the following is a demonstration of this law?

• When hydrogen and oxygen combine to make water, oxygen atoms are converted to hydrogen atoms.

• When sodium and chlorine combine to make salt, some of the sodium is always lost.

• When water breaks down into hydrogen and oxygen, the number of atoms always remains the same.

• When iron reacts with oxygen to form rust, the mass of the iron atoms increases.

Tags

NGSS.MS-PS1-5

Antonio conducts an investigation by adding reactants in a sealed container, as shown in the illustration. One of the reactants is 19g and the other reactant is 5g. After the reaction, Antonio can predict the total mass of the products of this reaction to be which of the following?

• 5g

• 14g

• 19g

• 24g

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A chemical reaction can be defined as an interaction of chemicals that produces new chemicals. An illustration of a chemical reaction is provided. Taking into account the law of conservation of mass, the most reasonable conclusion is that the missing product from the reaction illustrated here would consist of what?

• One oxygen atom and one hydrogen atom

• One chlorine atom and two hydrogen atoms

• One oxygen atom and three hydrogen atoms

• Two chlorine atoms and three hydrogen atoms

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following is true regarding the atoms involved in a chemical reaction?

• The same number of each type of atom will always be present before and after a chemical reaction takes place.

• Some of the atoms present before the reaction will always be lost during a chemical reaction.

• Some of the atoms will always be changed into a different type of atom by a chemical reaction.

• During a chemical reaction, atoms will always be combined into much larger molecules.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The law of conservation of mass states...

• Matter can neither be created nor destroyed. The mass of all the reactants must equal the mass of all the products.

• Matter can be created and destroyed in an open system. The mass of all the reactants must equal the mass of all the products.

• Matter can neither be created nor destroyed. The mass of all the reactants sometimes equal the mass of all the products.

• Matter can be created and destroyed. The mass of all the reactants must never equals the mass of all the products.

Tags

NGSS.MS-PS1-5

One reactant with a mass of 6 grams, is combined with another reactant, with a mass of 18 grams, in a sealed container. After the reaction, what is the most reasonable prediction for the total mass of the products of this reaction?

• 12g

• 4g

• 20g

• 24g

Tags

NGSS.MS-PS1-5

A chemical formula is a combination of element symbols and subscript numbers used to show the composition of a substance, either as a compound or in pure element form. Which of the following chemical formulas correctly demonstrates the law of conservation of mass?

• 
• 
• 
• 

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following is an example that includes evidence of a chemical change?

• A sample of zinc placed in water, and it settles to the bottom.

• A solid block is ice is heated, and it completely melts into a liquid.

• Sugar that is burned gives off an odor and turns brown and then black.

• A sample of mineral is broken down into smaller pieces.

Tags

NGSS.MS-PS1-2