Quiz 1a (09.11.2020)

Question 1

All nonzero digits are ____

Answer 1

significant

Question 2

Interior zeros are___

Answer 2

significant

Question 3

Leading zeroes (zeroes to the left of the first nonzero digit) are ____

Answer 3

not significant

Question 4

What are the rules about trailing zeros and significant figures?

Answer 4

if there is a decimal point, trailing zeros are significant

Question 5

What is the multiplication/division rule for significant figures?

Answer 5

the result carries the same number of significant figures as the factor with the fewest significant figures

Question 6

What is the addition/subtraction rule for significant figures?

Answer 6

the result carries the same number of decimal places as the quantity with the fewest decimal places

Question 7

Using units as a guide to solving problems is called _______. A unit equation is a statement of two equivalent quantities.

Answer 7

dimensional analysis

Question 8

A ______ is a fractional quantity of a unit equation with the units we are converting from on the bottom and the units we are converting to on the top.

Answer 8

conversion factor

Question 9

120 lbs = ___ Kg (There are 0.454 kg in one pound)

Answer 9

54.8 kg

Question 10

23 miles = ___ ft (There are 5280 feet in one mile)

Answer 10

121,440

Question 11

451 mL = __ ounces (there are 0.034 ounces in one milliliter)

Answer 11

15.3

Question 12

What are the three most important laws that led to the development of the atomic theory?

Answer 12

law conservation of mass, law of definite proportions, and law of multiple proportions

Question 13

Antoine Lavoisier formulated the Law of Conservation of Mass, which states the following:

Answer 13

in a chemical reaction, matter is neither created or destroyed

Question 14

What is the law of definite proportions?

Answer 14

All samples of a given compound, regardless of their source or how they were prepared have the same proportions of their constituent elements (sometimes called the law of constant composition)

Question 15

A compound of N and H contains 14g of N for every 3 g of H. What is the mass ratio?

Answer 15

4.7 : 1

Question 16

What is the law of multiple proportions?

Answer 16

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

Question 17

Atoms with the same number of protons but a different number of neutrons are called _____.

Answer 17

isotopes

Question 18

The relative amount of each different isotope in a naturally occurring sample of a given element is a percentage called the ______ of the isotopes

Answer 18

natural abundance

Question 19

The sum of the number of neutrons and protons in an atom is its _______.

Answer 19

mass number

Question 20

How many sig figs are in 23,000

Answer 20

2

Question 21

How many sig figs are in 4000.00

Answer 21

6

Question 22

How many sig figs are in 0.00023040?

Answer 22

5

Question 23

How many sig figs are in 400?

Answer 23

1

Question 24

Write 0.00333 in scientific notation.

Answer 24

3.33 x 10^-3

Question 25

Round 0.090035 to 3 sig figs.

Answer 25

0.0900

Question 26

Round 14,090 to 3 sig figs.

Answer 26

14,100

Question 27

658.0 + 23.5478 + 1345.29 = ____

Use sig figs

Answer 27

2026.8

Question 28

23.7 x 3.8 (Use sig figs)

Answer 28

90.

Question 29

________ is sometimes called atomic weight or standard atomic weight. It represents the average mass of the isotopes that compose that element weighted according to the natural abundance of each isotopes.

Answer 29

atomic mass

Question 30

The masses of atoms and the percent abundances of isotopes of elements are measured using ________ = a technique that separates particles according to their mass

Answer 30

mass spectrometry

Question 31

Positive ions are _____.

Answer 31

cations

Question 32

Negative ions are ____.

Answer 32

anions

Question 33

What are the properties of metals?

Answer 33

good conductors of heat and electricity, can be pounded into flat sheets (malleability), can be drawn into wires (ductility), shiny, tend to lose electrons

Question 34

What are the properties of nonmetals?

Answer 34

poor conductors, not ductile, not malleable, they tend to gain electrons

Question 35

What are the properties of metalloids?

Answer 35

semimetals, have mixed properties, semiconductors because of their immediate (and highly temperature dependent) electrical conductivity

Question 36

Name the periodic table trends.

Answer 36

Noble gases (8) - mostly unreactive, Alkali metals (1) - all reactive, Alkaline earth metals (2) - fairly reactive, Halogens (7) - very reactive nonmetals