Chemistry Basics (T1) Flashcards
What is the scientific method?
“A logical method of problem solving”
- making observations that lead to a question
- forming a hypothesis to answer the question
- testing the hypothesis by experiments
- making a conclusion based on the results of the experiment
What is a quantitative observation?
An observation involving numbers and units
What is a qualitative observation?
An observation that does not involve numbers and units
What is a hypothesis and what three points must it be able to do?
“An educated guess”
A good hypothesis..
- explains an observation
- can be tested
- will predict and outcome
What is a variable?
Variables are factors that can be changed
What is a ‘control variable’?
A variable that is held constant
What four factors make up a good experiment?
1) only two variables are allowed to change
2) the manipulated/independent variable is changed by the scientist
3) the responding/dependent variable changes as a result of the experiment
4) all other variables are controls as they are held constant
What is the manipulated/independent variable?
A variable that is changed by the scientists
What is the responding/dependent variable?
A variable that changes as a result of the experiment
What are physical properties? Give six examples.
Physical properties can be observed without chemically changing matter.
- malleability
- density
- colour
- texture
- mass
- solubility
What are chemical properties? Give five examples.
Chemical properties describe how a substance interacts with other substances.
- reactivity
- combustibility
- flammability
- acidity
- ability to rust
What do we mean when we say there has been a physical change?
The substance has changed physically but there is no change in the identity of the substance
What is a chemical change?
One or more new substances have been produced
Give four examples of physical changes..
- tearing
- crushing
- grinding
- phase changes
Give two examples of chemical changes..
- combustion of gas
- acid rain
