Law of Conservation of Mass
Fill in the blank: The mass of the reactants should ____________ the mass of the products
Equal
What two substances are absorbed by a plant during photosynthesis?
Carbon dioxide and water
List the starting substances (ingredients) for cellular respiration
Glucose and Oxygen
Ice melts into liquid water. Is this a physical or chemical change, and why?
Physical change — the substance is still water (H₂O); only the state changes.
A material made of only one type of atom is called what?
An element.
What does the law of conservation of mass state?
Matter (mass) cannot be created nor destroyed.
What are the two substances that are produced by a plant during photosynthesis?
Glucose and Oxygen
What substance is has its bonds broken down in order to produce energy and carbon dioxide as a biproduct?
Glucose
A piece of paper burns and turns into ash, smoke, and gases. What type of change is this?
Chemical change — new substances are formed.
Salt (NaCl) is made of sodium and chlorine chemically combined. Is it a pure substance or a mixture?
A pure substance (compound).
When mixing vinegar and baking soda in an open container, the mass seems to “disappear.” What most likely happened?
Gas escaped into the air.
What is the written equation for photosynthesis?
carbon dioxide + water + energy (light) → glucose + oxygen
What is the written equation for cellular respiration?
Glucose + Oxygen → Carbon Dioxide + Water + Energy (heat)
Salt dissolves in water. Physical or chemical change?
Physical change — the salt can be recovered by evaporation; no new substance forms.
A bowl of cereal with milk where you can see the different parts is what type of mixture?
A heterogeneous mixture.
What happens to atoms when the undergo a chemical reaction?
They are rearranged into a new substance.
If I were to put a leaf in a cup of water and bubbles began to form, what type of gas is being released?
Oxygen Gas (O2)
Why does increased cellular respiration during exercise cause people to breathe faster?
More oxygen is needed to produce more energy, and more carbon dioxide waste must be removed from the body.
Iron reacts with oxygen to form rust. What kind of change is this?
Chemical change — rust (iron oxide) is a new substance.
Air is made of nitrogen, oxygen, carbon dioxide, and other gases. Is air a pure substance or a mixture?
A mixture (homogeneous solution).
A reaction starts with 12 g of oxygen and 3 g of carbon. What is the expected mass of the carbon dioxide produced?
15g of CO2
How would placing a plant in a dark room for 24 hours affect the rate of photosynthesis?
The rate of photosynthesis would decrease and the plant would take in less carbon dioxide.
A student claims plants don’t need mitochondria because they make glucose during photosynthesis. What evidence shows this claim is incorrect?
Plant cells still need to grow and replicate in order for the plant to grow so they still need mitochondria to break down glucose and make energy (ATP) through cellular respiration, especially at night when photosynthesis cannot occur.
A cake batter turns into a solid, fluffy cake when heated. Physical or chemical change?
Chemical change — heat causes new substances to form during baking.
Two liquids are mixed and look the same throughout. However, they can be separated by distillation. What type of mixture is this?
A homogeneous mixture.