Properties of substances
Fill in the blank: The temperature at which a solid becomes a liquid is called its ________________________.
melting point
True or false: Substances that are good electrical conductors are usually also good thermal conductors?
True
Miss Mona is making a matcha, using matcha powder and hot water. What is the solute, solvent, and solution.
The matcha powder is the solute, the hot water is the solvent, and the final matcha is the solution.
Is a chemical change reversible or irreversible?
Irreversible
What is a fair test?
An experiment where only one variable is changed to answer a question (or any other similar but true definition).
Fill in the blank: A ____________ of a substance is something that makes it different from other substances, or something that helps you tell it apart from other substances.
property
Why do we use metal for pots and pans?
Because it is a good thermal conductor; It will allow the heat to reach the food that needs to be cooked
The ___________ of dissolving increases if we heat a solution.
rate
What happens in a chemical change?
A substance changes into a new substance
Is dissolving a chemical reaction? Yes or no.
No.
Name 3 properties of substances
Any of the following: boiling point, melting point, thermal conductivity, electrical conductivity, colour, density.....
Why do we put rubber on the outside of wires?
To prevent the electricity from moving into our hands and electrocuting us; rubber is a poor electrical conductor.
What factors increase how quickly a solute dissolves?
stirring, increase in temperature
The way we know that a chemical reaction has happened is called _______________.
Evidence
Why do cooking oil and nail polish remover boil at different temperatures?
Boiling point is a property of a substance, so different substances will have different boiling points.
Fill in the blank: The temperature at which particles throughout a liquid become a gas is called its _________.
Boiling point
Name 2 examples of good thermal conductors and 2 examples of poor thermal conductors.
Good thermal conductors: any metal (copper, silver, aluminium, iron, steel etc.), graphite
Poor thermal conductors: wood, rubber, plastic, wool
If you put sugar into a cold glass of water, will it eventually dissolve? Why or why not?
Yes, because particles are always moving. With time, the particles will interact with each other, move into the spaces between one another, and spread out/ dissolve.
describe the difference between reactants and products
reactants are the substances that interact in a chemical reaction, the product is the new substance that is produced.
reactant+ reactant= product
Why does heating make a solute dissolve faster?
Heating makes the particles move faster, spread out more quickly into the spaces between the solvent particles, and dissolve faster.
Similar: Both are a change of state from liquid to gas
Different: Evaporation can happen at any temperature while boiling only happens when a substance is heated; boiling produces bubbles while evaporation does not; boiling is quicker than evaporation
Is graphite a good electrical conductor?
Name 3 examples of physical changes
Name 3 examples of chemical reactions
burning a match, rusting, baking a cake, food rotting...
I am doing an experiment to see whether sugar dissolves faster in Coca cola or water. Name the independent variable, dependent variable, and 3 control variables of my experiment.
Independent variable: Type of liquid (Coca Cola or Water)
Dependent variable: time it takes to dissolve
Control variables: amount of liquid, temperature of liquid, solute, amount of solute, container shape...