Unit 1 (Intro)
The SI unit for electric current.
What is the Ampere?
What are the three phases of matter?
solid, liquid, gas
What charge does an electron have?
negative
What type of decay produces a particle with a +2 charge?
alpha
Half-life is the amount of time it takes for a radioactive sample to decrease its mass by how much?
half (50%)
Burning a candle is a ____________ change while melting wax is a _____________ change.
Chemical; physical
What is it called when a solid becomes a liquid?
Melting
What is the average atomic mass for mercury?
200.59
What type of nuclear reaction is shown below?
25299Es + 10n --> 5021Sc + 20078Pt + 310n
fission
Half-life is a ______________ for a given isotope.
constant
Convert the following to scientific notation:
0.000456
4.56 x 10-4
What three phase changes are Endothermic?
melting, boiling (evaporation), sublimation
How many protons are in an atom of Vanadium?
23
1.5 neutrons:1 proton
If the half-life of a substance is 14.7 years, and you start off with 98 grams of the substance, how much will remain after THREE half-lives?
12.25 g
0045060.0
0045060.0
What phase has a fixed volume and variable shape?
liquid
How many neutrons are in bromine-81?
46
Balance the following equation:
20884Po --> __________ + 42He20482Pb
If the half-life of a substance is 113 years, how many half lives will it take for a 45 g sample to decay into 1.40625 g?
5
Write the following value using the correct SI units in scientific notation.
25000 nm
2.5 x 10-5 m
On a heating curve, where does the potential energy increase?
phase changes (the flat lines)
Look at Boron on your periodic table. It has two isotopes, boron-10 and boron-11. Based on the average atomic mass, decide which you think is MOST common and calculate the number of neutrons there should be in MOST boron atoms.
6
Balance the following equation.
157N + 63Li --> ______ + 210n
1910Ne
If the half-life of a substance is 790 years, how long in years will it take for a 18 g sample to decay into 1.125 g?
3,160 years