Midterm

Question 1

What are the states of matter?

Answer 1

Solid, Liquid, Gas

Question 2

Liquid

Answer 2

no definite shape, but have a definite volume, able to flow

Question 3

Solids

Answer 3

definite shape and volume not compressible

Question 4

Gas

Answer 4

no definite shape or volume, molecules very far apart

Question 5

Elements

Answer 5

the simplest type of substance with unique physical and chemical properties. Consist of only 1 atom that cannot be broken down into simpler substances by chemical or physical means

Question 6

Compounds

Answer 6

a structure that consists of two or more atoms that are chemically bound together thus behaves as an independent unit

Question 7

heterogeneous

Answer 7

consists of two or more phases of variable composition that differ in properties (ie. oil floating in water)

Question 8

Homogeneous

Answer 8

has the same properties and composition throughout the sample. (ie. saltwater to brine is a homogeneous aqueous solution)

Question 9

Who created the periodic table?

Answer 9

Dmitri Mendeleev

Question 10

physical properties

Answer 10

properties measured without changing the chemical composition of the substance

Question 11

Chemical properties

Answer 11

substances potential to react with some other substances in its enviornment

Question 12

mass

Answer 12

measure of the amount of matter in a sample

Question 13

Volume

Answer 13

measure the amount of space the matter takes up

Question 14

Density

Answer 14

the ratio of an object’s mass to its volume

Question 15

Weight

Answer 15

based on gravity

Question 16

All non zero numbers are (BLANK)

Answer 16

significant

Question 17

Zeros in between digits or numbers are (BLANK)

Answer 17

significant

Question 18

Trading zeros are significant when there is a decimal (BLANK) them

Answer 18

before (ie. 505.400 has 4 sig figs)

Question 19

Leading zeros are (BLANK)

Answer 19

not significant

Question 20

Hoe many sig figs. are in 0.00751

Answer 20

3

Question 21

Zeros at the end of digits, when their is no decimal point are (BLANK)

Answer 21

ambigious

Question 22

10000 has how many sig. figs.

Answer 22

1

Question 23

672001 has how many sig. figs.

Answer 23

6

Question 24

For addition, subtraction, multiplication and division. your answer should have (BLANK) number of decimal points

Answer 24

fewest (ie. 7.821- 2.1 = 5.7)

Question 25

When using sig. figs in math round (BLANK)

Answer 25

the final answer

Question 26

accuracy

Answer 26

how close a measurement is to the real value

Question 27

precision

Answer 27

reproducibility or how close the measurements are to each other

Question 28

What is Aristotle's theory on matter and atoms?

Answer 28

proposed an continuous model of matter without atoms

Question 29

The law of conservation of mass

Answer 29

mass is neither created nor destroyed in a chemical reaction but merely changes form

Question 30

law of definite proportions

Answer 30

a compound is always made up of the same relative masses of elements that composed it.

Question 31

What does forensic science deal with

Answer 31

the application of science to legal matters and crime solving

Question 32

which of the following states of matter is generally considered the most ordered?

Answer 32

solid

Question 33

copper sulfate, CuSO4, is sometimes used to create the blue color in toilet water. Copper sulfate is an example of what?

Answer 33

a compound

Question 34

Pure substances

Answer 34

have a uniform composition and cannot be separated by physical methods

Question 35

The mobile phase in thin-layer chromatography is often

Answer 35

a liquid such as water

Question 36

to whom does credit for the creation of the periodic table go?

Answer 36

Dmitri Mendeleev

Question 37

Which element uses the symbol Na

Answer 37

Sodium

Question 38

What atomic symbol corresponds to iron

Answer 38

Fe

Question 39

Which of the following atomic symbols represents the coinage metals, copper, silver, and gold.

Answer 39

Cu, Ag and Au

Question 40

Which of the following elements are metals?

Answer 40

Iron, lead, calcium

Question 41

In the case study described in Chap 1 why didn't Agent Rawalt believe the Mexican government's claim about the death of the informant?

Answer 41

The color of the soil from the bodies didn't match the color of the soil from the ranch they were supposedly found

Question 42

Which of the following measures how much matter is contained in a simple?

Answer 42

Mass

Question 43

What is the difference between mass and weight

Answer 43

Weight is a measure of the pull of matter to the earth, while mass is a measure of how much matter is in a sample

Question 44

How many sig. figs. are there in the number 0.00204

Answer 44

3

Question 45

How many sig. figs. does 23.120 have

Answer 45

5

Question 46

Good accuracy and good precision in three measurements means that all three have what in common

Answer 46

value close to each other and close to the true value

Question 47

When a material floats in water, what is its density

Answer 47

less than 1.0 g/mL

Question 48

What 2 measurements determine density, and in what relationship to each other?

Answer 48

mass divided by volume

Question 49

What is the density of a material with a mass of 23.9g and a volume of 27.5 mL

Answer 49

0.869 g/mL

Question 50

How did Pitera's shovel provide evidence of his burying bodies?

Answer 50

The shovel still had soil on it specific t the burial site

Question 51

DNA evidence cannot be used to identify remains in a funerary urn, for what reason?

Answer 51

Cremation destroys all DNA

Question 52

The continuous model of matter, postulated by Aristotle, believed in what is the smallest material

Answer 52

nothing was; matter should be able to be divided over and over.

Question 53

The law of conservation mass states

Answer 53

mass is neither created nor destroyed in a chemical reaction, but merely changes form.

Question 54

What is the mass of the missing material in the following equation? (BLANK) g carbonic acid (22.0g CO2 + 9.0 g H2O)

Answer 54

31.0 g

Question 55

According to Daltons Atomic Theory, how do atoms combine?

Answer 55

in whole number ratios

Question 56

The compounds NO and NO2 represent which of the postulates of Daltons' atomic theory?

Answer 56

Atoms combine in simple, whole number ratios to form compounds

Question 57

Which sub-atomic particle has a positive charge

Answer 57

proton

Question 58

Rutherford's gold foil experiment proved what the matter?

Answer 58

That it has regions of dense, positive charge.

Question 59

How are two samples of an element referred to when they possess differing numbers of neutrons?

Answer 59

as isotopes

Question 60

What is the ground state of an atom

Answer 60

the state in which all electrons are in the lowest possible energy level.

Question 61

An electron that has been pushed into a higher energy level is said to be in what state?

Answer 61

an excited state

Question 62

What is the orbital of an electron?

Answer 62

the region of space with the highest probability of finding the electron

Question 63

An s orbital has what shape

Answer 63

spherical

Question 64

How could forensic chemists tell if a sample from the inside of a funerary urn was cement instead of human ashes?

Answer 64

The percentage of silicon was much higher in cement (about 19%) than in human ashes (about 1%)