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