concepts
Which of the following is NOT true?
a. A theory cannot be disproven even when there is a new observation that conflicts with the theory.
b. A chemist mixes sodium with water and witnesses a violent reaction between the two. This is best classified as an observation.
c. A law summarizes a series of related observations, while a theory attempts to explain why and predicts behavior beyond the current observations.
d. A hundred years ago, Svante Arrhenius suggested that the presence of heat-absorbing gases in the atmosphere might increase the average temperature of the ground. This is an example of a hypothesis.
e. Choose this answer if all of the above are true.
a. A theory cannot be disproven even when there is a new observation that conflicts with the theory.
They can be disproven all the time, because they are not factual, laws are.
Acetone has a density of 0.7857 g/cm3. How many liters of acetone are in 2.54x1012ng acetone? 1 cm3= 1 mL
3.23 L
A laser has a power rating of 5.60 mW in 1.5 hr, laser emits 8.25x1019 photons. What is the wavelength (in nm) of the laser?
Hint: 1 W= 1 J/s.
542 nm
Boron has two natural isotopes: B-10 with a mass of 10.0129 amu and B-11 has a mass of 11.0093 amu. Calculate the natural abundance of B-11
80%
33S2-
which of the following is NOT true?
a. In the nuclear model of the atom, protons and neutrons form a positively charged nucleus, while the electrons occupy the most space that is the rest of the atom.
b. You must consider both the protons and neutrons to determine the identity of an element.
c. Thomson measured the charge-to-mass ratio of the electron by deflecting cathode rays with both electric and magnetic fields.
d. the ion of P-33 with a 3- charge would have 15 protons, 18 neutrons, and 18 electrons
e. an isotope of calcium with 20 neutrons and 18 electrons must be 2+ ion with mass number 40.
B. You must consider both the protons and neutrons to determine the identity of an element.
just protons
You're planning on driving across the country with 6 friends for spring break, to a city 1388 miles away (one way). Your van averages 19.7 miles per gallon. The average cost of gasoline is $2.52 per gallon. How much will each person need to pay toward gas for the trip (both there and back), assuming the cost is evenly divided between you and your 6 friends?
$59.2
Calculate the de Broglie wavelength in pm of a xenon gas atom moving 169 m/s
18 pm
Chlorine contains 2 naturally occurring isotopes: Cl-35 (34.969) and Cl-37 (36.966). What Mass of Cl-37 is contained in a 2.79 sample of chlorine.
0.676g
What is the symbol for an atom with 24 electrons, 33 neutrons and 3+ ions
60Co 3+
Which of the following is/are true?
1. Se Forms a 2- ion based on its position in the periodic table
2. Na forms a 1+ ion based on its position in the periodic table
3. Pb forms a 4- ion based on its position in the periodic table
4. Ba forms a 2- ion based on its position in the periodic table
1 & 2
After seeing a physician, a patient adds regular exercise and adjust his daily calorie intake to lose 30.4 lb of body fat. If 1.00 lb of body fat is lost for every 1.46x104 kJ of energy burned beyond what is consumed, how many days will it take for the patient to meet his goal if he burns an additional 636 Calories per day than he consumes?
1 calorie (cal)= 4.184 J; 1 Cal= 1000 cal
167
The de Broglie wavelength for a hydrogen atom is 1410 pm. What is its velocity in m/s
281 m/s
On a particular meteor, calcium is only found as Ca-44 (isotopic mass of 43.955 amu) and Ca-40 (isotopic mass of 39.963). If 95.20% of calcium is Ca-44, what is the apparent atomic mass of Ca on this meteor?
43.76 amu
Here is a list of numbers, in order say how many sig figs are in each one
1.9783.6
2. 0.050
3. 0.55
4. 0.0000000900
5. 0.00000070
1. 5
2. 2
3. 2
4. 3
5. 2
Rank the following by decreasing energy for the electromagnetic radiation described.
1. radio waves from a station broadcasting at 107.9 MHz
2. orange light
3. green light
4. ultraviolet light radiation
5. infrared (IR) radiation)
4>3>2>5>1
The land speed record is held by the ThrustSSC with a speed of 1,227.985 km/h. How long would it take in minutes to drive this car the 59 miles from campus to fort smith at top speed?
Note: 1 mile= 1,609.34 m
4.64 min
261
Fictional element has 3 naturally occurring isotopes. Atomic mass 315.112 amu. 1st isotope 305.0015 amu and a natural abundance of 24.95%. 2nd isotope: 312.001 and a natural abundance of 9.996%. What is the mass of the 3rd isotope?
319.46amu
Which of the following is not true?
a. an isotope of calcium with 20 neutrons and 18 electrons must be a 2+ ion with mass number of 40
b. 3+ ion of the isotope Fe-53 must have 27 neutrons and 23 electrons
c. an atom of chlorine for which A=37 would have 17 protons, 17 electrons, and 20 neutrons.
d. an atomo has an atomic number of 53 and 79 neutrons in its nucleus must be i-32
e. choose this answer if it all correct
e. all
Which of the following IS/are true?
n=5, l=0, ml = -1, ms = ½ is a valid set of quantum numbers
An electron with the quantum numbers n=3, l=2, ml=1, ms=½ and an electron with the quantum numbers n=3, l=1, ml=1, ms=-½ are in the same subshell
There are exactly 5 orbitals in an atom that can have the quantum numbers n=4, l=2
The principal quantum number corresponds to the size and energy of an orbital; the angular momentum quantum number corresponds to the shape of the orbital
3 & 4
An electron in a hydrogen atom transitions from n=6 to n=1. Find the frequency of the emitted photon in Hz.
3.15E15 Hz
Silicon has three naturally occurring isotopes: Si-28, Si-29 (28.9765 amu and a natural abundance 4.667%) and Si-30 ( mass of 29.9738 and a natural abundance of 3.120%). Calculate the mass of Si-28
27.98amu
Identify the element if a sample of the element with a mass of 80.78g contains 4.500x1024.
B