Law of Conservation of Mass

The following reaction takes place in a closed system and the Law of Conservation of Energy is observed. A + B -------> C. There are 7g of reactant A and there are 18 g of product C. How many grams of reactant B?

• 7g

• 5g

• 11g

• 14g

Tags

NGSS.MS-PS1-5

What is the law of conservation of mass?

• The amount of matter changes when reacted or changed.
• The mass of all reactants are changed during a physical or chemical change
• The mass of the reactants equals the mass of the products
• The mass of the products is different than the mass of the reactants.

Tags

NGSS.MS-PS1-5

Students do an experiment to react baking soda with vinegar inside a plastic bag. Which of the following would provide the evidence that the number of atoms present before a chemical reaction is equal to the number of atoms present after the chemical reaction?

• The mass of the plastic bag, baking soda, and vinegar before the reaction was equal to the mass after the reaction.

• Bubbles were produced during the reaction, which meant that a gas was being produced.

• The plastic bag did not change in any way, indicating that it was not involved in the reaction.

• The mass of the baking soda was exactly equal to the mass of the vinegar used to create the chemical reaction.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

According to the Law of Conservation of Mass, the total amount of matter (atoms) in a closed system before and after a chemical reaction remains the same.

• True

• False

Tags

NGSS.MS-PS1-5

Suppose a reaction were to happen in an open container in a lab. During the reaction, the scientist observes the chemicals bubble and produce a gas. During the analysis the scientist notices that the reactants weighed 20 g when he started, and the product weighed 18 g. Explain what happened.  

• His chemical reaction defied the law of conservation of mass
• The product destroyed mass during the reaction
• The reactants created matter during the reaction
• The gas that was produced was not able to be weighed since the container was open.  

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

The Law of Conservation of Mass states that the total amount of matter ______________ after it undergoes change.

• disappears

• stays the same

• weighs less

• explodes

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Based on the Law of Conservation of Matter, describe the relationship between the mass of the reactants and the mass of the products.

• The mass of the products is always greater than the mass of the reactants.

• The mass of the reactants is less than the mass of the products.

• The mass of the reactants equals the mass of the products.

• The mass of the reactants is greater than the mass of the products.

Tags

NGSS.MS-PS1-5

Which picture below would correctly demonstrate the Law of Conservation of Matter if this picture is the reactants?

• 
• 
• 
• 

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

The law of conservation of mass says substances can neither be _______ nor ___________.

• Built; torn down

• Blended together; separated

• Created; destroyed

• Condensed; extracted

Tags

NGSS.MS-PS1-5

In a chemical reaction, 11 grams of sodium must combine with how many grams of chlorine to produce 15 grams of table salt?

• 4 grams

• 7 grams

• 8 grams

• 10 grams

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

NGSS.MS-PS1-1