Chemistry Midterm Quizlet
What is an isotope?
Atoms of the same element that have different numbers of neutrons
What is the density formula?
D=m/v (m=mass, v=volume)
What type of data goes on the y-axis?
Dependent Variable
What is the formula for energy of a photon?
Energy = h(Planck's constant) f(frequency)
What is the law of conservation of energy?
Energy cannot be created or destroyed
How does the law of conservation of energy affect calorimetry?
Energy does not come just exist so it must come from someplace to enter the system
What does a heating curve show?
How a substance's temperature changes as it absorbs heat
How does a nucleus become stable?
If the particles that makeup become balanced.
What type of data goes on the x-axis?
Independent Variable
How does change in energy affect state of matter?
It affects the heat which alters the state of matter
What are intrinsic properties?
Physical properties that are not dependent on how much of the substance is present.
What are extrinsic properties?
Physical properties that change depending on the amount of the substance present.
5. A piece of metal weighing 59.047 g was heated to 100.0 °C and then put it into 100.0 mL of water (initially at 23.7 °C). The metal and water were allowed to come to an equilibrium temperature, determined to be 27.8 °C. Assuming no heat lost to the environment, calculate the specific heat of the metal
Qwater=1713.8 J Cmetal=0.402 J/g Celcius
What is specific heat?
The amount of energy needed to raise the temperature of 1 gram of a substance by 1 degree Celsius.
Why does temperature stay constant during phase changes of water?
The heat is being used to break bonds between the molecules
What happens if the neutron/proton ratio is not ideal what happens?
The isotope becomes unstable
What components of an isotope must be balanced before and after nuclear decay?
The mass and atomic numbers must be equal
How do molar mass and moles relate?
The molar mass is the amotic mass in grams/mole
What is the formation of particles like in a solid?
The particles are tightly packed and ordered
What happens to the neutron/proton ratio as the atoms get larger?
The ratio of neutron/proton increases
What is a mole?
The relative formula mass of a substance in grams
What is a half-life?
The time taken for the radioactivity of a specified isotope to fall to half its original value.
What is an independent variable?
The variable that is manipulated
What is a dependent variable?
The variable that is measured
What is the formation of particles like in a liquid?
They are packed close together, but there is no regular arrangement
What is the movement of particles like in a gas
They are vibrating and moving freely at high speeds
What is the movement of particles in a liquid like?
They are vibrating and sliding past each other
How do the different types of radiation differ?
They differ in mass and energy
What is the movement of particles in a solid like?
They vibrate but generally do not move from place to place
What is the formation of particles in a gas
Well separated with no regular arrangement
A sample of element X contains 100 atoms with a mass of 12.00 and 10 atoms with a mass of 14.00. Calculate the average atomic mass (in amu) of element X.
X-12=90.9% X-14= 9.1%
What type of radiation is released when the neutron/proton ratio is too low?
alpha radiation
What are the 3 types of radiation?
alpha, beta, and gamma radiation
What type of radiation is released when the neutron/proton ratio is too high?
beta radiation
In mcAt what does aT mean?
change in temperature
How do you calculate the frequency of light?
frequency=velocity/wavelength
What direction does energy flow?
hot to cold
In mcAt what does M mean?
mass
How do you calculate the mass of an unknown isotope?
multiply the percentage of abundance of the atom by the atomic mass
How do you calculate the mass number?
protons + neutrons
What formula is used to calculate change in energy?
q=mc∆T
How can calimetry be used to calculate flow of energy?
show where energy is gained and lost
In mcAt what does C mean?
specific heat
What is the band of stability?
the location of stable nuclei on a neutron-vs.-proton plot
What is the formula for the wavelength of light?
wavelength= velocity/frequency
Rocks are sometimes used along coasts to prevent erosion. If a rock needs to weigh 2,000 kilograms (about 2 tons) in order not to be shifted by waves, how big (what volume) does it need to be? You are using basalt, which has a typical density of 3200 kg/m3
.625 m^3
What is the density of water?
1 g/cm3
What is the density of mercury (13.6 g/cm^3) in terms of kg/m^3)
1.36x10^4 kg/m^3
Answer this equation using the right amount of significant figures... 8.578 / 4.33821
1.977
The half-life of Zn-71 is 2.4 minutes. If one had 100.0 g at the beginning, how many grams would be left after 7.2 minutes has elapsed?
12.5 grams
How many grams of water can be heated from 20.0 Celcius to 75 Celcius using 12500.0 Joules?
120 grams
Naturally occurring iodine has an atomic mass of 126.9045. A 12.3849 g sample of iodine is accidentally contaminated with 1.0007 g of I-129, a synthetic radioisotope of iodine used in the treatment of certain diseases of the thyroid gland. The mass of I-129 is 128.9050 amu. Find the apparent "atomic mass" of the contaminated iodine.
127.0540amu
100.0 grams of an isotope with a half-life of 36.0 hours is present at time zero. How much time will have elapsed when 5.00 grams remains?
155.6 hours
Answer this equation using the right amount of significant figures... 34.683 + 58.930 + 68.35112
161.964
Calculate the molar mass of FeCl3?
162.3 g/mol
How many moles are 1.20 x 10^25 atoms of phosphorous?
19.9 moles
Answer this equation using the right amount of significant figures... 36.01 - 0.4 - 15
21
Write equation for nuclear reaction when Americium-241 undergoes alpha decay
241 237 4 95 AM --> 93 Np + 2 He
Complete the following equation by adding the missing element? 27 4 ? 1 13 Al + 2 He--> ? + 0n
27 4 30 1 13 Al + 2 He--> 15 P + 0n
How many significant figures are in 1.40x10^3
3
You have a rock with a volume of 15cm3 and a mass of 45 g. What is its density?
3.0 g/cm^3
How many particles are there in 1.43 g of a molecular compound with a molar mass of 233 g?
3.70 x 10^21 particles
Calculate the molar mass of Ga2(So3)3
379.7 g/mol
What is specific heat capacity of water?
4.186 J/gC (J=joule, gC= gram per degree celcius)
Answer this equation using the right amount of significant figures... 57 x 7.368
4.2 x 10^2 or 420
How many significant figures are in the measurement 34.6209 grams?
6
What is Avogadro's number?
6.02 x 10^23
How many seconds are in 2.0 years? (using significant figures)
6.3x10^7
What is Planck's constant?
6.626 x 10^-34