Chem unit 4

Question 1

Si base units

Answer 1

Time: second
Amt. of Substance:Mole
Length:meter
Mass: kilogram
Electric Current:Amphere
Luminous intensity: candela
Temperature: Kelvin

Question 2

Derived SI units: combo of base units

Answer 2

Volume: m3
Area: m2
Density: g/cm3
Molar mass: g/mol
Concentration: mol/L

Question 3

Accuracy:

right answer

Answer 3

Precision: not right answer, same answer alot

Question 4

Significant Figures

Answer 4

more SF, more prescise

Question 5

Scientific notation

Answer 5

exponent positive: right
negative: left
(number has to be smaller than 10)

Question 6

SF rules

Answer 6

• non zero
• sanwhiched zeros
• trailing zeros if decimal is present

Question 7

SF rules not SF

Answer 7

• not leading zero

- trailing zero w/no decimal

Question 8

SF in equation

Answer 8

sub/add: keep everything b4 the decimal.

Multi/Division: least of total # of SF for all

Question 9

Metric Units (weird)

Answer 9

T=tera 12
G=giga 9
M=mega 6
μ=micro -6
n=nano -9
p=pico -12

Question 10

Metric Conversion

Answer 10

TGMkhdbdcmμnp

Question 11

Radioactivity

Answer 11

unstable ratio of protons and neutrons, nuclei breaks down

Question 12

Alpha particle

3rd

Answer 12

4/2 Helium
slow
Charge: 2+

Question 13

Beta particle

2nd

Answer 13

electrons are emitted.
o/-1 e
β
Charge: -1

Question 14

Gamma Ray

1st

Answer 14

photons (light)
Y
-accompany alpha&beta

Question 15

Radioactive decay

Answer 15

occurs until stable nucleus is formed. alpha, beta, gamma. new elements form

Question 16

Positron Emmision

Answer 16

beta particle w/ opposite charge (e=), proton converted into neutron

Question 17

Electron capture

Answer 17

nucleus draws in surrounding e-, usually from lowest energy level; electron combines w/ proton to form neutrona

Question 18

Half-life

Answer 18

time required for half of radioisotope’s nuclei to decay

Question 19

Fission

Answer 19

splitting of nucleus. happens w/ mass larger than 60 that are unstable. atomic bomb. large energy is released. chain reaction w/ critical mass (mass to sustain) release energy

Question 20

Stablility of nuclei

Answer 20

n:p
1:1 smaller than proton of 20
1.5:1 bigger than proton of 20
(anything else undego radioactive decay to b stable)
anything w/ proton larger than 82 are radioactive)

Question 21

Nuclear force

Answer 21

strong: keep p & n together

Question 22

Fusion

Answer 22

combining of nuclei. happens w/ light nuclei, mass smaller than 60. release large amt of energy

Question 23

Fe is most stable

Answer 23

heavies in star, absorb