How do you know if something is an isotope?

they have the same atomic number but not necessarily the same atomic mass

If the density of nitrogen in air is 0.870 g/L, what mass (in kg) of nitrogen is contained in a room with dimensions of 13.3 m × 4.58 m × 2.43 m?

129kg

What is the correct answer to the following expression: (765.0 + 36.0) × 0.81150?

650

Express 0.00735 in scientific notation

7.35E-3

What is the percent mass of carbon, hydrogen and oxygen in acrolein, C3H4O?

C 64.26, H 7.2, O 28.54

Which element is most likely to form a 2+ ion?

N Mg Na S Al

Mg

What are the respective coefficients when the equation is balanced with the smallest whole numbers?

__ Al + __ FeO → __ Fe + __Al2O3

2 3 3 1

If 13.0 g N2 and 2.46 g H2 react to produce 1.30 g NH3, what is the percent yield of the reaction?

N2(g) + 3 H2(g) → 2 NH3(g)

9.4

Select the ions present in Ca3(PO4)2

Ca²⁺ PO₄ ^3-

Which of the following observations is/are examples of chemical change?

1. Sodium chloride melts at 801 0C.
2. The density of water decreases when it changes from a liquid to a solid.
3. The combustion of propane gas yields carbon dioxide and water

only 3

Which of the following formulas correctly match the given names?

1. dinitrogen tetroxide, NO4
2. cobalt(II) sulfate, Co2SO4
3. carbon tetrachloride, CCl4

3

Which of the following are covalent compounds?

1. CO2
2. HBr
3. Al2O3

1 2

Which of the following compounds are named correctly?

1. Ca(NO3)2, calcium(II) nitrate
2. K2CO3, potassium carbonate
3. Ca(OH)2, calcium hydroxide

2 3

You have 5.67 g of each of the following elements: Na, Ca, Pb, Ti and Zn. Which sample contains the largest number of moles?

Na

A compound containing nitrogen and oxygen is 69.55% by mass oxygen with a molecular weight of 92.02. What is the molecular formula for this compound?

N₂O₄

How many atoms of fluorine are present in 4.00 moles of NF3?

7.23E24

Which of the following statements concerning atomic structure is/are correct?

1- Neutrons and electrons are found in the nucleus.
2- In a neutral atom, the positive charge of the protons is balanced by the negative charge of the neutrons.
3- Electrons are negatively charged particles and surround the nucleus in the form of an electronic cloud

3

How many protons, electrons and neutrons are present in 40Ca2+?

20 P 18 e 20 N

Two students independently determine the volume of ethanol delivered by a 50.00-mL pipet. Each student takes 10 measurements, then calculates the average volume delivered and the standard deviation. The results are tabulated below.

AverageSt. Dev. Student A50.01 mL±0.02 mL Student B51.50 mL±2 mL
Which statement best describes the results?

A: good precision, good accuracy. B: poor precision, poor accuracy

Iron reacts with oxygen to produce iron(III) oxide.

4 Fe(s) + 3 O2(g) → 2 Fe2O3(s)

If 6.96 moles of Fe react with excess O2, how many moles of Fe2O3 can be formed?

3.48

Which statements below are true about homogeneous mixtures?

1. They have constant composition.

2. They are uniform throughout.

3. They are composed of pure substances that are chemically combined

2

Helium has 2 naturally occurring isotopes, He-4 (4.003 u) and He-3 (3.016 u). In an unusual sample of helium taken from a natural gas well the abundance of He-4 is 95.78%. What is the average atomic mass of this sample of helium?

3.961

For the following reaction 0.224 moles of nitrogen are allowed to react 0.416 moles of hydrogen. What is the limiting reagent and how much ammonia can be produced?

N₂(g) + 3H₂(g) 2NH₃(g

H₂ 0.277

Which have the same mass?
1. 5.5 x 10^-3 kg
2. 5.5 x 10³ g
3. 5.5 x 10¹² ng

2 3

What is the ground state electron configuration for P^3-?

[Ne]3s²3p⁶

What are the oxidation numbers of sulfur in each of the following compounds SF₆, S₂F₁₀ and SF₄, respectively?

+6 +5 +4

All of the following sets of quantum numbers are allowed EXCEPT

n = 2, l= 0, m_{l =} +1

n = 3, l= 0, m_{l =} 0

n = 4, l = 2, m_l = –1

n = 5, l = 3, m_l = +2

n = 2, l = 1, m_l = 0

1

What is the ground state electron configuration for F?

[He]2s²2p⁵

If 103 mL of 1.84 M HCl(aq) is diluted with water to a volume of 926 mL, what is the molarity of the diluted HCl(aq)?

.205

The pH of an aqueous HI solution is 4.08. What is the H3O+ concentration of the solution?

8.32E-5

Which of the following are diamagnetic?

1. Li
2. Mg
3. N

2

If a cordless phone operates at a frequency of 46.7 MHz. What is the wavelength of this radiation?

6.4 m

What is the net ionic equation for the reaction of copper(II) hydroxide and hydrochloric acid?

Cu(OH)₂(s)+2H⁺(aq)Cu²⁺(aq)+2H₂O(l)

Which of the following compounds are soluble in water?

1. Ca₃(PO₄)₂
2. CuCH₃COO
3. CuCO₃
4. Cu₂S

2

What is the net ionic equation (NIE) for the reaction of aqueous sodium bromide and aqueous lead(II) nitrate?

Pb⁺²(aq)+ 2Br^-(aq) PbBr₂(s)

What is the mass of potassium iodide in 112 mL of 4.61E-2 M KI(aq)?

.857

For a hydrogen atom, calculate the wavelength of an emitted photon in the Lyman series that results from the transition n = 6.00 to n = 1.00. Rydberg constant is 1.097E+7 m^–1.
(h = 6.626E-34 J×s and c = 2.998E+8 m/s)

93.8 nm

What is the net ionic equation for the reaction of potassium hydroxide and hydroiodic acid?

H⁺(aq)+OH^-(aq)H₂O(l)

What is the ground state electron configuration for Co²⁺?

[Ar]sd⁷

Which species in the below reaction is the reducing agent?

Zn(s)+ 2Ag+(aq)Zn2+(aq)+ 2Ag(s)

Zn(s)

Which of the following sets of quantum numbers refers to a 3p orbital?

n=3, l=1, ml=-1

Which of the following statements about the atomic structure model is/are correct?

1- According to quantum theory, electrons are in orbits around the nucleus at quantized energy levels.
2- Rutherford's experiment proved that most of the atom is empty space, and the protons are in the nucleus.
3- According to quantum theory, electrons are in an electronic cloud around the nucleus

2 3

A 21.46 mL sample of NaOH is titrated with 27.78 mL of 0.1591 M HCl(aq). What is the concentration of the NaOH solution

.2060

What is the net ionic equation (NIE) for the reaction of aqueous ammonium sulfide and aqueous calcium nitrate?

Ca²⁺(aq)+ S^2-(aq) CaS(s)

What are the spectator ions in the reaction between aqueous ZnCl₂ and aqueous K₃PO₄?

K⁺ Cl^-

What is the ground state electron configuration for Si?

[Ne] 3s² 3p²

R

1.097E-7

h

6.626E-39

c

2.998E-10

average atomic mass

(% abundance/100)* mass plus any additional

# orbitals in shell

n²

# orbitals in subshell

2L+1

Aufbau

lower levels filled first

Pauli

only 2 e^- per orbitals with opposite spins

Hund

singly occupied before doubling up

Long Wavelengths vs short wavelengths

long wavelength -> low frequency, low energy, short line

short wavelength -> high frequency, high energy, long line

formal charge

valence e^- - (LPE + 1/2 BE)

how many particles/atoms in 1 mole

6.022E23

bond order trend

single is longest and weakest

triple is strongest but shortest

atomic radius trend

increases going down and decreases going right

Exothermic

Expansion

system working ON surroundings

H < 0 q < 0 w< 0

surroundings get warmer

Endothermic

Compression

surroundings effect system

H > 0 q > 0 w > 0

surroundings get colder