8.P.1.3 8.P.1.4

Substances present at the start of a chemical reaction

• subscripts

• coefficients

• reactants

• products

Tags

NGSS.MS-PS1-5

Which is the BEST explanation of why heat is released when wood burns?

• Burning creates energy by stopping particle motion

• Burning destroys matter and creates energy with it.

• Burning releases energy stored in chemical bonds.

• Burning causes convection currents which create heat energy.

Tags

NGSS.MS-PS1-4

In a chemical formula, what information does the coefficient give you?

• number of molecules present of the compound

• how the compound is physically arranged

• how the compound reacts with other compounds

• how many atoms of each element in the compound

Which statement best describes the change to an ice cube as it melts?

• The change is physical because the mass remains the same.

• The change is physical because the substance remains the same.

• The change is chemical because water has a different pH than ice.

• The change is chemical because ice has a lower density than water.

Tags

NGSS.MS-PS1-4

Which best explains why conservation of mass should be studied in a closed system?

• To prevent the loss of any reactants or products.

• To prevent contamination of the products.

• To prevent release of precipitates formed

• To prevent the absorption of heat from the outside

Tags

NGSS.MS-PS1-5

How many protons are in Sodium?

• 11

• 22

• 12

• 33

Tags

NGSS.MS-PS1-1

How many electrons are in Aluminium?

• 40

• 27

• 13

• 14

Tags

NGSS.MS-PS1-1

How many neutrons are in Magnesium?

• 36

• 12

• 24

• 6

Tags

NGSS.MS-PS1-1

How many electrons are in Sulfur?

• 32

• 16

• 48

• 8

Tags

NGSS.MS-PS1-1

How many electrons are in Potassium?

• 19

• 20

• 58

• 39

Tags

NGSS.MS-PS1-1