Which change is chemical?(1 point)
Responses
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 freezing: liquid water becoming solid water
water undergoing electrolysis: liquid water becoming oxygen and hydrogen molecules
Which number remains unchanged during photosynthesis?(1 point)
Responses
the number of carbon atoms
the number of carbon atoms
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 glucose molecules
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
total mass
total mass
arrangement of the atoms
arrangement of the atoms
A young snake eats and digests a mouse. The increase in the snake’s mass equals(1 point)
Responses
only the mass of the mouse
only the mass of the mouse
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.
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 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
6
6
4
4
2
6
The change that is chemical is "water undergoing electrolysis: liquid water becoming oxygen and hydrogen molecules."
To determine which change is chemical, we need to understand the difference between physical and chemical changes.
A physical change is a change where the substance involved does not change its chemical composition, only its physical properties. For example, when water evaporates or boils, the water is changing from a liquid to a gas, but its chemical composition (H2O) remains the same. This is a physical change.
On the other hand, a chemical change is a change where the substance involved undergoes a chemical reaction, resulting in a new substance or substances with different chemical properties. In the case of water undergoing electrolysis, a chemical reaction occurs where the water molecules (H2O) are broken down into their elemental components, oxygen (O2) and hydrogen (H2). This is a chemical change.
Therefore, the correct answer is "water undergoing electrolysis: liquid water becoming oxygen and hydrogen molecules."