Which change is chemical?
water evaporating
water boiling
water undergoing electrolysis
water freezing
water undergoing electrolysis
the number of carbon atoms
arrangement of the atoms
The balanced equation for cellular respiration is:
C6H12O6 + 6O2 -> 6CO2 + 6H2O + Energy
Therefore, the coefficient for water after cellular respiration is 6.
Which number remains unchanged during photosynthesis?
the number of water molecules
the number of glucose molecules
the number of carbon atoms
the number of carbon dioxide molecules
In a chemical reaction, which aspect of the reactants changes?
total mass
arrangement of the atoms
name of each element
nuclei
A young snake eats and digests a mouse. The increase in the snake's mass equals
only the mass of the mouse
the mass of the mouse plus the original mass of 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 the waste produced by the snake.
Cellular respiration transforms glucose and oxygen into carbon dioxide, water, and energy. What is the coefficient for water after cellular respiration?
To determine which change is chemical, we need to understand the difference between a chemical change and a physical change.
A chemical change, also known as a chemical reaction, occurs when one or more substances are transformed into different substances with different properties. This change involves the breaking and forming of chemical bonds.
On the other hand, a physical change is a change in appearance or state of a substance without changing its chemical identity. It involves alterations in the physical properties such as shape, size, or phase, but the composition of the substance remains the same.
Now, let's analyze the changes you mentioned:
1. Water evaporating: This is a physical change. Evaporation occurs when the liquid water changes into water vapor due to an increase in temperature. It is still water but in the gaseous state.
2. Water boiling: This is also a physical change. Boiling happens when liquid water is heated to its boiling point, and it transforms into water vapor. Similar to evaporation, the substance remains water but in the gaseous state.
3. Water undergoing electrolysis: This is a chemical change. Electrolysis is a process where an electric current is passed through water, causing the water molecules to undergo a chemical reaction. It splits water into its elemental components - hydrogen gas (H2) and oxygen gas (O2).
4. Water freezing: This is a physical change. Freezing occurs when liquid water is cooled below its freezing point, resulting in the formation of ice. Although the state of water changes from liquid to solid, it remains water.
In conclusion, out of the four changes mentioned, only water undergoing electrolysis is a chemical change.