Which change is chemical?(1 point)

Responses

water freezing: liquid water becoming solid water
water freezing: liquid water becoming solid water

water evaporating: liquid water becoming gaseous water
water evaporating: liquid water becoming gaseous water

water boiling: solid water becoming gaseous water
water boiling: solid water becoming gaseous water

water undergoing electrolysis: liquid water becoming oxygen and hydrogen molecules
water undergoing electrolysis: liquid water becoming oxygen and hydrogen molecules

water undergoing electrolysis: liquid water becoming oxygen and hydrogen molecules

Which number remains unchanged during photosynthesis?(1 point)

Responses

the number of glucose molecules
the number of glucose molecules

the number of water molecules
the number of water molecules

the number of carbon dioxide molecules
the number of carbon dioxide molecules

the number of carbon atoms

the number of carbon atoms

In a chemical reaction, which aspect of the reactants changes?(1 point)

Responses

name of each element
name of each element

nuclei
nuclei

arrangement of the atoms
arrangement of the atoms

total mass

arrangement of the atoms

A young snake eats and digests a mouse. The increase in the snake’s mass equals(1 point)

Responses

the mass of the mouse minus the mass of waste produced by the snake.
the mass of the mouse minus the mass of waste produced by the snake.

the mass of the mouse plus the mass of waste produced by the snake.
the mass of the mouse plus the mass of waste produced by the snake.

only the mass of the mouse
only the mass of the mouse

the mass of the mouse plus the original mass of the snake.

the mass of the mouse plus the mass of waste produced by the snake.

Cellular respiration transforms glucose and oxygen into carbon dioxide, water, and energy.



C6H12O6 + 6O2 → 6CO2 + ?H2O + Energy



Based on the law of conservation of matter, what is the missing coefficient for water?

(1 point)
Responses

8
8

2
2

6
6

4

6

The change that is chemical is water undergoing electrolysis. Water electrolysis is a chemical reaction in which an electric current is passed through water to break it down into its constituent elements, oxygen and hydrogen. This process involves a chemical change, as the water molecules are being chemically decomposed into different substances. The other changes listed, such as water freezing, water evaporating, and water boiling, are physical changes because they do not involve the breaking or formation of bonds between atoms in the water molecules. Instead, they involve changes in the state or phase of the substance.