MOTION & FORCES
A car travels at a constant speed. Is it accelerating? Why/why not?
No, because its speed is not changing.
What force pulls objects toward Earth?
Gravity
Name one sign of a chemical reaction.
Color change/gas/temperature change/precipitate/light
What are the two main types of chemical bonding?
Ionic and covalent
Who proposed the first atomic theory?
Dalton
What unit is used to measure force?
Newton (N)
Who discovered the law of gravitation?
Isaac Newton
What must happen in a chemical equation?
It must be balanced.
Which bond involves sharing electrons?
Covalent bonding
Who discovered the electron?
J.J. Thomson
A car travels 120 km in 2 hours. What is its speed?
60 km/h
What is the difference between mass and weight?
Mass is the amount of matter; weight is gravitational force.
Balance:
H₂ + O₂ → H₂O
2H₂ + O₂ → 2H₂O
Which bond usually forms between metals and non-metals?
Ionic bonding
Which scientist proposed the nucleus?
Rutherford
What is the difference between speed and velocity?
Velocity includes direction.
Would your mass change on the Moon?
No, only weight changes.
What is a reactant?
A starting substance in a reaction.
Why do atoms form bonds?
To become more stable/to complete their outer shell
Which model introduced electron energy levels?
Bohr model
A box is pushed right with 30 N and left with 12 N. What is the net force?
18 N to the right
Why do astronauts float in space?
Because they are in continuous free fall (microgravity).
What type of reaction releases energy?
Exothermic reaction
What happens to electrons in ionic bonding?
They are transferred.
Why was Rutherford’s model important?
It showed atoms have a small dense nucleus.