Term 1 Flashcards
What are pure substances?
Substances that have a definite and constant composition. They can be classified as either an element or a compound.
What is a mixture?
They are physical combinations of pure substances that have NO definite or constant composition. They can be classified as either homogeneous or heterogeneous.
What is a homogeneous mixture?
A mixture that has a uniform composition throughout.
What is a heterogeneous mixture?
A mixture that has a non-uniform composition throughout.
What is the law of conservation of mass?
The law states that; In any chemical reaction the mass of the reactants is equal to the mass of the products.
What are Isotopes?
Elements that have a varying number of neutrons but ALWAYS the same number of protons.
What is the atomic mass of elements based off?
It is based off the average of the masses of the element’s isotopes, taking into consideration the percentage abundance.
What are ions?
They are atoms that have gained or lost electrons.
What does the law of definite proportions state?
Every chemical compound contains fixed and constant proportions (by weight) of its constituent elements.
What does the law of multiple proportions state?
When two elements combine with each other to make one or more compounds, the ratios of the masses of one element that combines with the fixed mass of the other are simple whole numbers.
How do you determine error?
Error = experimental value - accepted value
How do you find percentage error?
Percentage error = error/accepted value * 100
When and how do you round to the appropriate decimal place?
When adding or subtracting, that answer should be rounded to the number of decimal places as the number with the least decimal places.
When and how do you round to the appropriate significant figure?
When multiplying or dividing, the answer should be round to the nearest appropriate significant figure.
What are the SI units for temperature and the amount of substance?
Temperature: Kelvin (K); K = *C + 273
Amount of substance: Moles (mol.)
