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Flashcards in Chapter 3 Deck (56):
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What is accuracy?

how close the measured value is to the true value

1

what is precision

upon making repeated measurements, how close the measured values are to each other

2

Which are you improving when you calibrate an instrument?

accuracy

3

Significant digits are used for what kind of values?

measured

4

What types of numbers do you disregard the sig digs?

counting
conversion factors
constants

5

SI unit for mass

kilogram kg

6

what does second measure

time

7

What does m represent and measure

meter
length

8

si temperature?

kelvin

9

difference between metric and SI

kilogram vs. gram

10

difference between mass and weight?

weight is a force that measures the pull of gravity on a given mass
mass is a measure of the amount of matter that an object contains

11

How to convert celsius and kelvin?

K=C + 273
C=K-273

12

Unit to measure the volume of a solid

centimeter cubed

13

units to measure the volume of a liquid

mL
L

14

conversion factor for volume

1 cm cubed
___________
1mL

15

Anything divided by itself equals

1

16

What are the equations for density?

d=m/v
m=dv
v=m/d

17

what is density

the ratio of the mass of an object to its volume

18

What kind of property is density and why?

intensive - depends on composition not size

19

What happens to the density of a material if the temperature goes up?

density generally decreases

20

what is a measurement

a quantity that has both a number and a unit

21

Why is it important to make correct measurements?

measurements are fundamental to experimental sciences

22

what happens in scientific notation

a given number is written as the product of two numbers: a coefficient and 10 raised to a power

23

What must happen to evaluate the accuracy of a measurement

the measured value must be compared to the correct value

24

what must happen to evaluate precision

you must compare the values of two or more repeated measurements

25

what is the accepted value

the correct value based on reliable references

26

what is the experimental value

the value measured in the lab

27

what is error

the difference between the experimental value and the accepted value

28

formula for error

experimental value - accepted value

29

what is percent error

the absolute value of the error divided by the accepted value multiplied by 100%

30

percent error equation

I error I
-------- X100
accepted value

31

what are significant figures

all of the digits that are known, plus a last digit that is estimated

32

why must measurements always be reported to the correct number of significant digits?

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

33

In general, a calculated answer cannot be __________ than the least precise measurement from which it was calculated

more precise

34

5 common SI units

meter
kilogram
kelvin
second
mole

35

SI for amount of substance

mole

36

SI for luminous intensity

candela

37

SI for electric current

ampere

38

mole abbreviation

mol

39

candela abbreviation

cd

40

ampere abbreviation

A

41

what is volume

the space occupied by any sample of matter

42

what is temperature

a measure of how cold or hot an object is

43

what happens with heat

it travels to the lower temperature area

44

kelvin freezing and boiling points

273.15 and 373.15

45

what is absolute zero

zero on Kelvin

46

what is energy

the capacity to do work or to produce heat

47

what are common units of energy

joule and calorie

48

which is si for energy

joule

49

what exactly is a calorie

amount of heat it takes to raise the temperature of 1g of pure water by 1 degree C

50

conversion factor joules to calories

1 J = 0.2390 cal
1 cal = 4.184 joules

51

what is a conversion factor

a ratio of equivalent measurements

52

measurements in a conversion factor....

the numerator is equal to the denominator

53

when a measurement is multiplied by a conversion factor,

the numerical value generally changes, but the actual size remains the same

54

what is dimensional analysis

a way to analyze and solve problems using the units, or dimensions, of the measurements

55

what are easily solved using dimensional analysis

problems in which a measurement with one unit is converted to an equivalent measurement with another unit