Chemistry 152T Test #1 - Lecture

Question 1

What are significant figures?

Answer 1

(Important Numbers) - Non place holding digits in a measurement - Way of rounding in chemistry - helps keep answer precise (represent precision of a measured quantity).

Question 2

You round to a number of significant figures to keep your answer _______________?

Answer 2

Precise - “A chain is no stronger than its weakest link.”

Question 3

What can change a measurement?

Answer 3

The instrument you use.

Question 4

What is precision?

Answer 4

Decimal place that you can measure to.

Question 5

More significant figures = _____________?

Answer 5

More precise answer.

Question 6

Place Holder zeros (are/are not) significant figures? Why?

Answer 6

They are not significant figures because if you take these away, you change the actual number.

Question 7

How many significant figures are in 1.5 * 10^3?

Answer 7

2 significant figures.

Question 8

How many significant figures are in 1.50 * 10^3?

Answer 8

3 significant figures.

Question 9

How many significant figures are in 150o?

Answer 9

3 significant figures.

Question 10

How many significant figures are in 1500.?

Answer 10

4 significant figures.

Question 11

How many significant figures are in 1.500 * 10^3?

Answer 11

4 significant figures.

Question 12

How many significant figures are in 1.0 (repeating 0’s)?

Answer 12

Infinite number of significant figures.

Question 13

There is always ________________ in measurement.

Answer 13

uncertainty.

Question 14

All nonzero numbers are (significant/not significant)?

Answer 14

Significant.

Question 15

Zeros in between nonzero numbers are (significant/not significant)?

Answer 15

Significant.

Question 16

Trailing zeros (zeros to the right of a nonzero number) that fall after a decimal point are (significant/not significant)?

Answer 16

Significant.

Question 17

Trailing zeros before a decimal point are (significant/not significant)?

Answer 17

Not significant, unless they have a bar over them or an explicit decimal point.

Question 18

Leading zeros (zeros to the left of the first nonzero number) are (significant/not significant)?

Answer 18

Not significant.

Question 19

Exact numbers have _______________ significant figures.

Answer 19

An infinite number of (Because they have no ambiguity) - These include counts, defined quantities, and integers in an equation.

Question 20

When you are multiplying and dividing significant figures, what happens?

Answer 20

The answer is limited by the number with the least significant figures.

Question 21

What is 5.02 * 89.665 * 0.10? Round with significant figures accordingly.

Answer 21

45 (45.0118 before rounding to least amount of significant figures).

Question 22

What is 0.0267 * 2.1? Round with significant figures accordingly.

Answer 22

0.056 (0.05607 before rounding to least amount of significant figures).

Question 23

What happens when you are adding or subtracting significant figures?

Answer 23

The answer is limited to the same number of places as the number with the least places.

Question 24

What is 0.664 - 0.65? Round with significant figures accordingly.

Answer 24

0.01 (0.014 before eliminating the extra place).

Question 25

What happens when you take the average of significant figures?

Answer 25

Answer must have the same amount of significant figures as the number with the least amount of significant figures.

Question 26

Explain Accuracy vs. Precision.

Answer 26

Accuracy is the closeness to the true (accepted) value, whereas precision is the reproducible ability (closeness of values to each other).

Question 27

Accuracy is measured by ___________?

Answer 27

Percent Error.

Question 28

What is the percent error formula?

Answer 28

((Measured value - Accepted value) / Accepted Value) * 100 - ***This is the way accuracy is measured.

Question 29

A low percent error = more ______________ results.

Answer 29

Accurate.

Question 30

What are two ways that you can measure the volume of a cylinder?

Answer 30

Water displacement or the dimensions (actual formula) - V=(pi)r^2h

Question 31

What are three ways to measure body fat percentage?

Answer 31

Sensor, Caliber, Water Displacement.

Question 32

Precision is measured by ___________?

Answer 32

Standard Deviation.

Question 33

What is Standard Deviation?

Answer 33

A bell curve (wider = less precise; thinner = more precise) - shows exponential growth and decay - ***This is the way precision is measured.

Question 34

What are the standard units of the metric system?

Answer 34

Mass = gram (g) Length - meter (m) Volume - liter (L)

Question 35

Metric System - What are the prefixes from largest to smallest and their symbols?

Answer 35

``` Mega (M) Kilo (k) Hecto (h) Deca (da) Meter, Gram, Liter (m, g, L) Deci (d) Centi (c) Milli (m) Micro (weird M that looks like a U) Nano (n) Pico (p) ```

Question 36

Metric System - Prefix: Mega - What is the exponent?

Answer 36

10 ^ 6

Question 37

Metric System - Prefix: Kilo - What is the exponent?

Answer 37

10 ^ 3

Question 38

Metric System - Prefix: Hecto - What is the exponent?

Answer 38

10 ^ 2

Question 39

Metric System - Prefix: Deca - What is the exponent?

Answer 39

10 ^ 1

Question 40

Metric System - Prefix: Meter, Gram, Liter - What is the exponent?

Answer 40

10 ^ 0

Question 41

Metric System - Prefix: Deci - What is the exponent?

Answer 41

10 ^ -1

Question 42

Metric System - Prefix: Centi - What is the exponent?

Answer 42

10 ^ -2

Question 43

Metric System - Prefix: Milli - What is the exponent?

Answer 43

10 ^ -3

Question 44

Metric System - Prefix: Micro - What is the exponent?

Answer 44

10 ^ -6

Question 45

Metric System - Prefix: Nano - What is the exponent?

Answer 45

10 ^ -9

Question 46

Metric System - Prefix: Pico - What is the exponent?

Answer 46

10 ^ -12

Question 47

What are the 3 Methods of Metric Conversion?

Answer 47

1) Move Decimal Place (to larger unit - move to left; smaller unit - move to right) 2) Proportion 3) Factor Label Method (Dimensional Analysis) - map out unit and multiply by known conversion factor.

Question 48

425 mg = ____________ grams?

Answer 48

.425 grams

Question 49

.48 km = ___________ meters?

Answer 49

480 meters

Question 50

0.025 kg = ____________ mg?

Answer 50

25,000 mg

Question 51

652 cm = ____________ km?

Answer 51

0.00652 km

Question 52

6.0 * 10^-5 microliters = ____________ mL?

Answer 52

6.0 * 10^-8 mL

Question 53

*1 kg = _____________ lbs?

Answer 53

2.20 lbs

Question 54

*1 inch = ________________ cm?

Answer 54

2.54 cm

Question 55

*1 Liter = ________________ qt?

Answer 55

1.06 qts

Question 56

*1 yard = ___________ ft?

Answer 56

3 ft

Question 57

*1 gallon = ________________ qt?

Answer 57

4

Question 58

*1 qt = ______________ fl. oz.?

Answer 58

32 fl. oz.

Question 59

*1 ton = _____________________ lbs?

Answer 59

2,000 lbs.

Question 60

148 lbs = _________________ kg?

Answer 60

67.3 kg

Question 61

5.850 m = _______________ yd?

Answer 61

6.398 yds

Question 62

What is different about cubic conversions?

Answer 62

You need to cube the whole conversion factor

Question 63

5.5 m^3 = _________________ dm^3

Answer 63

5.500 dm^3 (CUBIC CONVERSION - CUBE CONVERSION FACTOR)

Question 64

Density Formula

Answer 64

(mass/Volume) Mass is measured in grams Volume is measured in mL (cm^3)

Question 65

Density is a (intensive/extensive property)? Why?

Answer 65

Density is an intensive property because it doesn't change when you have more of the substance or less of the substance. (Metric conversions are extensive properties).

Question 66

An object was placed in 31.5 mL H2O and the volume rose to 36.0 mL. If the mass is 21.560 g, find its density.

Answer 66

4.8 g/mL.

Question 67

What is the Kelvin temperature scale?

Answer 67

K = degrees Celsius + 273

Question 68

What is the melting point of H2O?

Answer 68

32 degrees Fahrenheit | 0 degrees Celsius = 273 K

Question 69

What is the boiling point of H2O?

Answer 69

212 degrees Fahrenheit | 100 degrees Celsius = 373 K

Question 70

What are the 3 steps of chemical formula writing?

Answer 70

1) List Charge (From periodic table or table D of polyatomic ions) 2) Criss Cross the charges 3) Reduce to simplest whole number ratio

Question 71

What are the nucleons? What are their charges and masses?

Answer 71

- Proton - Charge +1, Mass 1 AMU | - Neutron - Charge 0 (Neutral), Mass 1 AMU

Question 72

Electrons have a charge of ________?

Answer 72

-1

Question 73

What does valence mean?

Answer 73

In the outermost shell of the atom.

Question 74

_____ valence electrons in an atom produces stability.

Answer 74

8 (But capacity of the atom is actually higher).

Question 75

What is the importance of the outermost shell of an atom?

Answer 75

It gives the atom it's properties - This is what allows it to react with other elements.

Question 76

What are binary compounds?

Answer 76

Compounds formed between two different elements.

Question 77

What does a roman numeral mean in nomenclature?

Answer 77

It represents the charge of the metal.

Question 78

What element does an acid always have?

Answer 78

Hydrogen.

Question 79

What are binary acids?

Answer 79

Hydrogen with a nonmetal.

Question 80

What does aqueous (aq) mean?

Answer 80

That the element or compound dissolves in water (Acid).

Question 81

What is HCl (aq)?

Answer 81

Hydrochloric Acid.

Question 82

What is HF (aq)?

Answer 82

Hyrdofluoric Acid.

Question 83

What is H3P (aq)?

Answer 83

Hydrophosphoric Acid.

Question 84

What is a ternary (oxy) acid?

Answer 84

An acid that has the elements hydrogen and oxygen along with another element, often a nonmetal - DERIVED FROM POLYATOMIC IONS.

Question 85

In ternary (oxy) acids, what happens to the endings of the ion names?

Answer 85

ate -> ic | ite -> ous

Question 86

What is an isotope?

Answer 86

Same element with different number of neutrons - particular mass.

Question 87

What are the 3 isotopes of hydrogen?

Answer 87

1) Protium (Ordinary Hydrogen - Most abundant) 2) Deuterium (has 1 neutron) 3) Tritium (has 2 neutrons)

Question 88

How much mass does an electron have versus a proton/neutron?

Answer 88

Proton/neutron - 1 AMU | Electron - 1/1836 AMU

Question 89

What is an atomic mass unit (AMU) equal to?

Answer 89

1.66 times 10^-24 grams (This is equal to (1/2) mass of a carbon-12 Isotope).

Question 90

What are the 3 types of Radioactive Emission?

Answer 90

1) Alpha - Helium Nucleus (Charge +2) 2) Beta - Electron (Charge -1) 3) Gamma - Radiation (Charge - 0)

Question 91

Isotopes of an element have the same number of _________ but a different number of ______________.

Answer 91

Protons (Atomic #) | Neutrons (Mass #)

Question 92

What is the atomic weight?

Answer 92

The weighted average of the naturally occurring isotopes of an element.