8.5DE - Chemical Reactions & Formulas

Which of the following describes a precipitate?

• a liquid forms when a block of metal is heated
• a solid forms when one liquid is poured into another
• a gas forms when a solid is placed in a liquid
• bubbles form when an acid is poured on a rock

Tags

NGSS.MS-PS1-2

Which is NOT an indication of a chemical change?

• temperature change
• formation of a precipitate
• shape change
• production of light

Tags

NGSS.MS-PS1-2

What is the right part of a chemical equation called?
H_{2 +} O → H₂O

• Reactants
• Products 
• Yields 
• Chemical Equation 

The Law of Conservation of Mass states that -

• the number and type of atoms on both sides of a chemical reaction are equal

• there are more atoms on the reactant side than the product side

• there are more atoms on the product side than the reactant side

• the mass of the product will not equal the reactants

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

You know you a chemical reaction has occurred if:

• there is a precipitate.

• there is a permanent color change.

• there is a temperature change.

• All of these answers are evidence.

Tags

NGSS.MS-PS1-2

In the equation,

2Mg + O₂ ---> 2MgO, which are the reactants?

• 2Mg + O₂

• 2MgO

• 2Mg and MgO

• O₂ and MgO

Tags

NGSS.MS-PS1-1

At the end of chemical reactions, what is the total mass of the reactants compared to the total mass of the products?

• the product is doubled
• the product is half the mass of the reactants
• the mass is the same
• the mass changes depending on the reaction

Tags

NGSS.MS-PS1-5

Which of the following is a sign that a chemical reaction has occurred?

• change in shape
• melting
• formation of a gas
• dissolving

Is hammering wood together to build a house a chemical or physical change?

• chemical
• physical

Is melting butter for popcorn a chemical or physical change?

• chemical
• physical

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4