Mystery Gas!
What gas is produced when citric acid reacts with baking soda in a bath bomb?
Carbon Dioxide (CO2)
What is the law of conservation of matter?
Matter cannot be created or destroyed.
Name one sign that a chemical reaction might have occured.
gas produced, temperature change, color change, smell change, etc.
In a chemical reaction, what happens to the atoms of different molecules?
They break down and rearrange into new molecules.
What evidence shows that gas is being produced in the bath bomb reaction? List at least 2.
Bubbles, fizzing, foam, gas inflating a balloon, mass loss in open system, etc.
Give one reason why mass might have decreased during the balloon lab?
Is bubbling or fizzing always a sign of a chemical reaction? Why or why not?
No, not always. When water boils it produces bubbles, but that's a physical change, water changing its state from a liquid to a gas.
Are atoms created or destroyed during a chemical reaction?
No
If the reaction happens in a sealed bag instead of an open cup, what will happen to the mass?
The mass will stay the same (closed system).
What units do we typically use to measure mass and volume in a science lab?
Mass: grams (mg, g, kg)
Volume: liters (milliliters)
What is the difference between a physical change (like a change in state of matter) and a chemical reaction?
A chemical reaction rearranges atoms to generate new substances, in a physical change the molecules stay the same
If we consider a molecule of Hydrogen Peroxide (H2O2), how many atoms make up a single molecules? If I rewrite the chemical formula like this: 5H2O2, how does that change the representation of Hydrogen Peroxide?
Atoms in a single molecule: 4, 2 Hydrogen and 2 Oxygen
The large 5 means that there are 5 complete molecules of Hydrogen Peroxide
What properties of the gas helped us narrow it down to Carbon Dioxide?
Density - it sank, was less dense than air
Flammability - it extinguished the match, was not flammable
Why does a chemical reaction eventually stop?
One or more reactants (ingredients) run out, can't rearrange anymore.
Why isn't dissolving salt in water an example of a chemical reaction?
The salt and water molecules stay the same, the salt just gets broken into smaller and smaller pieces as it sticks to water molecules.
When scientists repeated John Dalton's experiments with water, what provided evidence that a water molecule had 2 Hydrogen atoms instead of just 1.
They noticed gas bubbles being produced at different rates, one was produced twice as fast as the other, leading them to conclude that there were twice as many hydrogen atoms as oxygen.
How could you prove the gas from the bath bomb reaction is NOT oxygen?