Chapter 2 - Measurements and Calculations Flashcards
How many base units does the SI system have?
Seven
What is a quantity?
Something that has magnitude, size, or amount
What is mass?
A measure of the quantity/amount of matter
What is weight?
A measure of the gravitational pull on matter
What is length?
A measure of distance
What do combinations of SI form?
Derived units
What is volume
The amount of space occupied by an object
What is density?
The ratio of mass to volume
D = m/v
What is a conversation factor?
A ratio derived from the equality between two different units that can be used to convert from one unit to another
What is dimensional analysis?
A mathematical technique that allows you to use units to solve problems involving measurements
The Factor-Label Method
H-bar
What is accuracy?
The closeness of measurements to the correct or accepted value or the quantity measured
What is precision?
The closeness of a set of measurements of the same quantity made in the same way
How do you calculate percentage error?
Subtracting the accepted value from the experimental value, dividing by the accepted value, then multiplying by 100, then take the absolute value
|(Value(ex) - value(acc)/value(acc) * 100|
What are significant figures?
All the digits known with certainty plus one final digit, which is somewhat uncertain or estimated
How do you know if two quantities are directly proportional?
If dividing one by the other gives a constant value
As one goes up, the other goes up
As one goes down, the other goes down
Straight positive line
How do you know if two quantities are inversely proportional?
If their product is constant
As one goes up, the other goes down
As one goes down, the other goes up
Hyperbola, gradual negative curve
What is the SI unit for mass?
Kilogram
How would you calculate significant figures in 45 times 30?
To one significant figure, since 30 only has one and in multiplication you round to the lowest number of significant figures
How would you calculate significant figures in 2.34 plus 3.4
To one digit after the decimal, since 3.4 has the lowest number of digits after the decimal, 1
