Chemistry revision 2.0

Particles must do what for a reaction to occur?

collide

what two conditions must collisions meet?

enough energy and correct orientation

what happens if particles don’t have enough energy?

no reaction occurs

what is activation energy?

the minimum energy needed to start a reaction

what is a synthesis reaction?

two or more substances combine to form one product

what is a decomposition reaction?

one substance breaks apart into simpler substances

what is a single displacement reaction?

one element replaces another in a compound

what is a double displacement reaction?

two compounds swap ions

what is combustion?

a substance reacts with oxygen releasing energy usually forming carbon dioxide and water

what is the criss cross method?

swapping ion charges to make a neutral compound

what must all compounds be overall?

neutral with no charge

what does balancing an equation mean?

having the same number of atoms on both sides

what can you change when balancing equations?

coefficients

what can you not change when balancing equations?

chemical formulas

how does temperature affect reaction rate?

higher temperature increases reaction rate

how does surface area affect reaction rate?

greater surface area increases reaction rate

what is a control variable?

something kept the same in an experiment

give examples of control variables?

volume of acid temperature and mass

what are the three basic experiment steps?

measure materials carry out reaction measure results

why does gas seem to disappear in a reaction?

it escapes into the air

how can you measure gas in a reaction?

using a balance to measure mass loss or collecting the gas