Chemistry (Pre-Brainscape)

Question 1

If there are 75.4 g, how many kg?

Answer 1

0.0754 kg

Question 2

Determine the density of an object that has a mass of 784 g and displaces 12.1 mL of water when placed in a graduated cylinder.

Answer 2

D = M/V; therefore the density of this object = 64.8 g/mL

Question 3

How many significant figures are in the following value:

7793.9

Answer 3

5

Question 4

How many significant figures are there in the answer to the following problem?

( 8.881 × 2.100) + 0.590 = ?

Answer 4

4

Question 5

The recommended adult dose of Elixophyllin, a drug used to treat asthma, is 5.6 mg/kg of body mass. Calculate the dose in milligrams for a 121-lb person. 2.2046 x 10^-3 lb = 1 g

Answer 5

307.4 mg

Question 6

Calculate the atomic mass of magnesium if magnesium has 3 naturally occurring stable isotopes with the following masses and natural abundances.

Mg-24 23.9996 amu 78.99%
Mg-25 24.9858 amu 10.00%
Mg-26 25.9826 amu 11.01%

Answer 6

24.32 amu

Question 7

Which of the following contains the fewest atoms?

10.0 g Rb
10.0 g Ca
10.0 g Mg
10.0 g Li
10.0 g Cs

Answer 7

10.0 g Cs, as it has the highest molar mass, therefore the lowest number of moles and the fewest atoms.

Question 8

How many H atoms are in 6.5 moles of H2O2?

Answer 8

6.5 moles * (6.02 * 10^23) * 2 H molecules = 7.8*10^24

Question 9

Which of the following transitions (in a hydrogen atom) represent emission of the shortest wavelength photon?

n = 5 to n = 4
n = 4 to n = 1
n = 1 to n = 3
n = 3 to n = 1
n = 3 to n = 5

Answer 9

n = 4 to n = 1

Question 10

Which of the following occur as the wavelength of a photon increases?

The energy increases.
The speed decreases.
Planck’s constant decreases.
The frequency decreases.
None of the above occur as the wavelength of a photon increases.

Answer 10

The frequency decreases

Question 11

Identify the correct values for a 3s sublevel.

n = 3, l = 0, ml = 0
n = 2, l = 0, ml = 0
n = 2, l = 1, ml = +2
n = 4, l = -1, ml = 0
n = 1, l = 0, ml = 0

Answer 11

n = 3, l = 0, ml = 0

Question 12

For n = 3, what are the possible sublevels?

Answer 12

0, 1, 2

Question 13

Place the following in order of decreasing radius.

Te2⁻ F⁻ O2⁻

Answer 13

NOTE: Left/down the table, radius increases

Te2⁻ > O2⁻ > F⁻

Question 14

Give the ground state electron configuration for Mg2⁺.

Answer 14

1s2,2s2,2p6

Question 15

Which of the following elements has chemical properties similar to selenium?

nitrogen
sulfur
hydrogen
fluorine

Answer 15

Sulfur

Question 16

How many valence electrons do the alkali metals possess?

Answer 16

1

Question 17

How many core electrons does a carbon atom possess?

Answer 17

2

Question 18

Which set of quantum numbers below is impossible?

n=1, l=1, ml=0, ms=-1/2
n=2, l=1, ml=-1, ms=+1/2
n=5, l=0, ml=0, ms=+1/2
n=1, l=0, ml=0, ms=-1/2
n=4, l=3, ml=2, ms=+1/2

Answer 18

n=1, l=1, ml=0, ms=-1/2

Question 19

A temperature of 403 K is _______________ degrees C?

Answer 19

130 degrees celsius

Question 20

The mass of a particular Pt nanoparticle is 6.97 x 10^-21 g. What is the volume of the nanoparticle if the density of Pt is 21.4 g cm^-3?

Answer 20

3.26x10^-21 cm^3

Question 21

What factor determines similar chemical properties for a set of elements?

Answer 21

Groups (columns in the periodic table)

Question 22

Ruthorford’s gold foil experiment determined that:

Answer 22

protons are concentrated in the center of an atom

Question 23

The cathode ray tube experiment determined that:

Answer 23

atoms are made of protons, neutrons, and electrons

Question 24

What is defined as the vertical distance from the midline of a wave to the top of the peak?

Answer 24

amplitude

Question 25

How many 5d orbitals are there in an atom?

Answer 25

5

Question 26

In a set of quantum numbers, if l = 0, m(l) can only be ___.

Answer 26

0

Question 27

In a set of quantum numbers, n represents the ____.

Answer 27

row

Question 28

What is the maximum number of electrons allowed in the third energy level?

Answer 28

18

Question 29

How many zinc atoms are in 545 g of zinc?

Answer 29

5.02 x 10^24