Modeling Conservation of Mass Assessment

A student is using the following key to model the chemical equation provided.

Chemical Equation

MgCl₂ +2NaF-> MgF₂ +2NaCl

The reactants are on the left and the products are on the right. How many blue beads will the student need to model each side of the equation?

• 
  1 for the products and 1 for the reactants

• 2 for the products and 2 for the reactants

• 2 for the products and 1 for the reactants

• 1 for the products and 2 for the reactants

Tags

NGSS.MS-PS1-1

Baking soda and vinegar have been mixed in a plastic bag.

Which of the following provides evidence that the number of atoms present before the 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 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

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-PS1-5

In a chemical reaction known as decomposition, carbonic acid breaks down into water, and what other compound?

• 
• 
• 
• 

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

NGSS.MS-PS1-1

Which of the following atomic models of chemical reactions correctly demonstrates the Law of Conservation of Matter?

• 
• 
• 
• 

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

What does the law of conservation of mass say about matter?

Tags

NGSS.MS-PS1-5

If I start with 40g of Hydrogen peroxide (H₂O₂) and it goes through a chemical change, how many grams of the final substance will I have?

• 20g

• 40g

• 45g

• 80g

Students are designing an experiment to test the law of conservation of mass using the following materials: 10 g baking soda, 30 mL vinegar, an electronic balance, and a resealable plastic bag.

Describe the basic procedure the students should follow to model this law.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2