Quiz 1

Question 1

Accuracy

Answer 1

How close a measurement comes to the actual value

Question 2

Precision

Answer 2

is an indication of how close repeated

measurements are to each other

Question 3

Law of Conservation of Mass

Answer 3

matter is neither created nor destroyed. Total mass before must equal the total mass at the end
total mass of reactants =total mass of products
Antoine Lavoisier

Question 4

Law of Definite proportions

Answer 4

Joseph Proust.
• All samples of a given compound, regardless of their source or how they were prepared, have the same proportions of their constituent elements

Question 5

Law of Multiple proportions

Answer 5

John Dalton
When two elements (call them A and B) form two different compounds, the masses of B that combine with 1 g of A can be expressed as a ratio of small, whole numbers

Question 6

Dalton’s Atomic theory

Answer 6

1. Each element tiny, indestructible particles called atoms
2. All atoms of an element have the same mass and other properties
3. Atoms combine in simple, whole-number ratios to form molecules
4. atoms of one element cannot change into atoms of another element they simply rearrange

Question 7

J.J. Thomson

Answer 7

• Believed that the cathode ray was composed of
tiny particles with an electrical charge
• Designed an experiment to demonstrate that
there were particles by measuring the amount
of force it takes to deflect their path a given
amount

Question 8

Thomson’s Experiment

Answer 8

Investigate the effect of placing an electric field around tube

1. charged matter is attracted to an electric field
2. light’s path is not deflected by an electric field

Question 9

Thomson’s conclusion

Answer 9

• If the particle has the same amount of charge as a hydrogen ion, then it must have a mass almost 2000x smaller than hydrogen atoms!
Later, Millikan showed that the particle did have the same amount of charge as the hydrogen ion
• The only way for this to be true is if these
particles were pieces of atoms
apparently, the atom is not unbreakable

Question 10

Plum Pudding Model

Answer 10

The structure of the atom contains many negatively charged electrons. Electrons in a positively charged
field (pudding)

Question 11

Observed Mass

Answer 11

is a weighted average of the weights of all the naturally occurring atoms

Question 12

mass number

Answer 12

sum of all the protons and neutrons in the nucleus.

Question 13

Periodic Law

Answer 13

when the elements are arranged in order of increasing atomic mass, certain sets of properties recur periodically