Quiz 1a (09.11.2020) Flashcards Preview

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Flashcards in Quiz 1a (09.11.2020) Deck (36)
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1

All nonzero digits are ____

significant

2

Interior zeros are___

significant

3

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

not significant

4

What are the rules about trailing zeros and significant figures?

if there is a decimal point, trailing zeros are significant

5

What is the multiplication/division rule for significant figures?

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

6

What is the addition/subtraction rule for significant figures?

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

7

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

dimensional analysis

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.

conversion factor

9

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

54.8 kg

10

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

121,440

11

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

15.3

12

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

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

13

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

in a chemical reaction, matter is neither created or destroyed

14

What is the law of definite proportions?

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)

15

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

4.7 : 1

16

What is the law of multiple proportions?

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.

17

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

isotopes

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

natural abundance

19

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

mass number

20

How many sig figs are in 23,000

2

21

How many sig figs are in 4000.00

6

22

How many sig figs are in 0.00023040?

5

23

How many sig figs are in 400?

1

24

Write 0.00333 in scientific notation.

3.33 x 10^-3

25

Round 0.090035 to 3 sig figs.

0.0900

26

Round 14,090 to 3 sig figs.

14,100

27

658.0 + 23.5478 + 1345.29 = ____
(Use sig figs)

2026.8

28

23.7 x 3.8 (Use sig figs)

90.

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.

atomic mass

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

mass spectrometry