SCH3U Units 1 & 2 Flashcards
What is chemistry?
It is the study of matter and its composition.
Name 6 things scientists do to be able to observe matter.
- Developing models
- Conducting experiments
- Seeking patterns
- Observing various types of chemical reactions
- Performing calculations based on known data
- Building continuously on the work and discoveries of other scientists.
What is matter?
It is anything that has mass and volume (takes up space).
Give some examples of qualitative physical properties.
Physical state, colour, odour, crystal shape, malleablility, ductility, hardness, brittleness, clarity, taste, texture.
Give some examples of quantitative physical properties.
Melting point, boiling point, density, solubility, electrical conductivity, thermal conductivity, height, mass, volume.
Give some examples of chemical properties.
Combustibility, toxicity, decomposition, and reactivity with water, air, pure oxygen, acids, pure substances.
What are the four rules of significant digits?
- All non-zero numbers are significant
- All seros that are located between two non-zero numbers are significant
- Zeros that are located to the left of a value are NOT significant.
- Zeros located to the right of a value may or may not be significant.
What is accuracy?
Accuracy refers to how close a given quantity is to an accepted or expected value.
What is precision?
Precision may refer to the exactness of a measurement.
What are physical properties & how can they be observed?
They can be observed without changing on form of matter into the other. They can be either quantitative or qualitative.
What are chemical properties and how can they be observed?
They are properties that can only be observed by changing matter from one form to the other.
What are physical changes?
PHysical changes are changes in appearance, but not what the substance is (appearance changes, but composition doesn’t).
What are chemical changes?
They change what the matter is (change the composition of the matter).
What are 5 indicators of a chemical change?
- Heat/light
- Precipitate
- Gas produced
- New colour
- Difficult to reverse
What is the rule for the number of significant digits that should be recorded in the answer to a multiplying or dividing calculation?
The value with the fewest number of significant digits going into the calculation is how many significant digits should be recorded in your answer.
What is the rule for how many significant digits should be recorded in the answer to a adding or subtracting calculation?
The value with the fewest decimal places going into the calculation indicates the number of decimal places you should record in your answer.
If a number that ends in 5 is being rounded, should the number be rounded up or down?
If the number preceding the 5 is odd, the number should be rounded up, but if it is even, the number should be rounded down.
What does the law of conservation of mass state?
During a chemical reaction, the total mass of the substances involved does not change.