Ch 3: Scientific Measurement

Question 1

Why is it important to be able to make measurements and decide whether a measurement is correct?

Answer 1

Measurements are fundamental to experimental sciences.

Question 2

How are all measurements made?

Answer 2

By comparing what you want to know with some type of standard (measuring tool).

Question 3

Measurements are not usually _____. Since they are ________, they have some ___________.

Answer 3

exact
estimates
uncertainty

Question 4

The estimate is only as good as the _________ ____.

Answer 4

measuring tool

Question 5

Uncertainty is communicated to imply how carefully we know the measurement. The uncertainty is in the ____ _____.

Answer 5

last digit

Question 6

Uncertainty is stated more explicitly by using ____/_____ ________.

Answer 6

plus/minus notation

Question 7

Scientific notation is used to _____ ____ _______ and _____ _______.

Answer 7

write large numbers
and
small numbers

Question 8

The powers of ten in scientific notation represent the _____ _____ or _________ (order of _________).

Answer 8

place value
or
magnitude
order of magnitude

Question 9

Scientific notation: if the power of 10 is positive, you ________ by that number of 10s.

Answer 9

multiply

Question 10

Scientific notation: if the power of 10 is negative, you ______ by that number of 10s.

Answer 10

divide

Question 11

To evaluate accuracy of a measurement, the measured value must be compared to the _______ _____.

Answer 11

correct value

Question 12

To evaluate precision of a measurement, the values of two or more ________ ____________ must be compared.

Answer 12

repeated measurements

Question 13

What is the equation for error?

Answer 13

Error = experimental value - accepted value

Question 14

What is the equation for percent error?

Answer 14

Percent error = |error| / accepted value X 100%

Question 15

Why must measurements always be reported to the correct number of significant figures?

Answer 15

Calculated answers often depend on the number of significant figures in the values used in calculation.

Question 16

Rules for determining significant digits: digits from - are always significant.

Answer 16

1-9

Question 17

Rules for determining significant digits: zeros _______ ___ other significant digits are always significant (________ zeros)

Answer 17

between two

sandwich

Question 18

Rules for determining significant digits: ___ or more additional zeros to the right of both the decimal place and another significant digit ___ significant.

Answer 18

one

are

Question 19

Rules for determining significant digits: zeros solely used for _______ ___ _______ _____ (placeholders) are not significant.

Answer 19

spacing the decimal point

Question 20

Rules for determining significant digits: _____ numbers or definitions of _____ have _________ or ________ number of significant figures.

Answer 20

exact
units
unlimited or infinite

Question 21

A calculated answer cannot be more precise than the _____ precise ___________ from which it was calculated.

Answer 21

least

measurement

Question 22

Rounding sig figs: _____ the number of significant figures in each ____ _____. Round the final answer to the _____ number of significant figures.

Answer 22

count
data point
least

Question 23

Addition and subtraction of sig figs: the answer to an addition or subtraction problem should be rounded to the ____ number of decimal places (not ______) as the measurement with the _____ number of decimal places.

Answer 23

same
digits
least

Question 24

Multiplication and division of sig figs: _____ the answer to the same number of significant figures as the measurement with the _____ number of significant figures.

Answer 24

round

least

Question 25

The five SI base units are the _____, the ________, the ______, the ______, and the ____.

Answer 25

meter
kilogram
Kelvin
second
mole

Question 26

Common metric units of length are…

Answer 26

centimeter
meter
kilometer

Question 27

Common metric units of volume include…

Answer 27

liter
milliliter
cubic centimeters
microliter

Question 28

What two equivalents units of temperature do scientists commonly use?

Answer 28

The degree Celsius and the Kelvin.

Question 29

What is the equation to go from Celsius to Kelvin?

Answer 29

K = °C + 273

Question 30

What is the equation to go from Kelvin to Celsius?

Answer 30

°C = K - 273

Question 31

What are common units of energy?

Answer 31

Joule and calorie

Question 32

When a measurement is multiplied by a conversion factor, the _________ value is generally changed, but the ______ ____ of the quantity measure remains the same.

Answer 32

numerical

actual size

Question 33

What provides you with an alternative approach to problem-solving?

Answer 33

Dimensional analysis

Question 34

What is the formula for density?

Answer 34

Density = mass / volume

Question 35

If density doesn’t depend on the size of an object, what does it depend on?

Answer 35

The composition of a substance.

Question 36

The heavier a substance, the ______ the density.

Answer 36

higher

Question 37

The density of pure water is _ g/mL at its most dense (_°C).

Answer 37

1 g/mL

4 °C

Question 38

Substances with densities lower than 1 g/mL will _____ in water.

Answer 38

float

Question 39

Substances with densities higher than 1 g/mL will ____ in water.

Answer 39

sink

Question 40

Mixtures of water and dissolved solids are ____ dense than water alone.

Answer 40

more

Question 41

The density of a substance generally _________ as its temperature increases.

Answer 41

decreases