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100

What is the molecular geometry and bond angle for boron trihydride?

trigonal planar; 120

100

Balance the chemical equation below: 

Al2(SO4)3 + Ca(OH)2 → Al(OH)3 + CaSO4

Al2(SO4)3 + 3 Ca(OH)2 → 2 Al(OH)3 + 3 CaSO4

100

Identify the reaction type for Fe(s) + CuSO₄(aq) → FeSO₄(aq) + Cu(s)

(combination, decomposition, combustion, single replacement, or double replacement).

single replacement

100

Select all statements that are consistent with the Kinetic Molecular Theory of gases.

A) Gas particles are in constant, random motion and their collisions with container walls cause pressure.
B) Gas particles occupy a significant fraction of the container’s volume.
C) Gas particles exert attractive and repulsive forces on each other under normal conditions.
D) The collisions between gas molecules are perfectly elastic (no energy is lost).

A, D

100

At constant T and P, 1.404 mol of a gas occupies 0.250 L. What volume (L) will 0.750 mol occupy under the same conditions?

  1. 0.134 L

  2. 0.250(0.750)/1.404; V2=V1n2/n1

200

What is the molecular geometry, bond angle, and polarity for carbon dioxide?

linear; 180; nonpolar

200

  1. Fe2++Cl2→Fe3++2Cl−        

  2. Which reactant is oxidized?

Fe2+

200

2 Al(s) + 3 CuO(s) → Al2O3(s) + 3 Cu(s).

You react 12.0 g Al with excess CuO. How many grams of Cu form?

42.4 g Cu

12.0 g (1 mol/26.9815 g) = 0.44475 mol Al

0.44475 mol Al × (3mol CuO/2 mol Al) = 0.66712 mol CuO

0.66712 mol CuO × 63.546 g/mol CuO

200

A 2.50 L sample of gas at 300.0 K and 1.20 atm is heated to 450.0 K while allowed to expand to 4.00 L. What is the final pressure?

1.13 atm

P2=P1V1T2/V2T1

(1.20× 2.50x 450)/(4.00×300)

200

A sample of Ar at 228.3 K experiences a change in volume from 63.5 L to 51 L. If its new pressure is 64212.4 torr at 782 K, what was its original pressure in torr?

15056 torr

P1=P2V2T1/T2V1=(64212.4 torr)(51 L)(228.3 K)/(782 K)(63.5 L)

300

What is the molecular geometry, bond angle, polarity, and IMFs in phosphorus trichloride?

trigonal pyramidal; 109; polar; london dispersion and dipole dipole

300

What is the number of moles of aluminum atoms in 1.204 × 10²⁴ atoms of Al?

2.00 mol Al


(1.204×1024 atoms) x (1 mol/6.022×1023 atoms) =2.00 mol

300

For 4 Fe(s) + 3 O2(g) → 2 Fe2O3(s), you have 10.0 g Fe and 8.00 g O2.
(a) Identify the limiting reactant. 

(b) Calculate the grams of Fe2O3 produced

Fe is limiting producing 14.30 g Fe2O3

Fe: 10 g Fe (55.845 mol/g) (2 mol Fe2O3/4 mol Fe) = 0.08953 mol Fe2O3

O2: 8 g O2 (32 mol/g) (2 mol Fe2O3/3 mol O2) = 0.16667 mol Fe2O3

0.08953 mol Fe2O3 (159.69 g/mol)

300

A gas mixture contains N₂ and CO₂. The partial pressure of N₂ is 625 torr, and the partial pressure of CO₂ is 0.715 atm.What is the total pressure of the mixture (in atm)?

1.54 atm

625 torr× (1atm/760 torr) = 0.822 atm

0.822+0.715=1.537 atm

300

A mixture of He, Ar, and Ne has Ptotal = 558 Torr. If PHe = 341 Torr and PNe = 112 Torr, what is PAr (in Torr)?

  1. 105 Torr

  2. 558−341−112=105 Torr

400

Rank the following in terms of increasing boiling point: 

LiCl,  C3H7OH,  C4H8,  N2

N2 < C4H8< C3H7OH < LiCl

400

How many atoms of O are there in 0.100 moles of glucose, C₆H₁₂O₆?

3.61 × 10²³ O atoms


0.100 mol C6H12O6 × (6.022×1023 atoms/mol) × (6 mol O2/ 1 mol C₆H₁₂O₆)

400

A reaction's reactant have a potential energy of 120 kJ·mol⁻¹ and the products have a potential energy of 70 kJ·mol⁻¹. (hint: drawing the energy diagram can help visualize this)
What is the ΔH (heat of reaction) and is it exotherimic or endothermic?

-50 kJ/mol (exothermic)

ΔH=Eproducts−Ereactants

70-120

400

A 5.00 L container at 25.0 °C holds a gas at 0.250 atm and that contained gas has mass = 3.50 g. What is the molar mass of the gas?

68.50 g/mol

25.0 °C = 298.15 K.

n = PV/(RT) = (0.250 × 5.00) / (0.08206 × 298.15) = 0.05109 mol

3.50 g/0.05109 mol = 68.50 g/mol

400

  1. What is the volume of 1.20 mol H₂ at STP?

  1. 26.9 L

  2. 1.20 mol(22.414 L/mol)=26.8968 L

500

Rank the melting points for the following: Ca(OH)2,   CH3CH2CH2OH,  CH3CH2CH2CH2OH,   CH3CH2OCH3

(Ca(OH)2 > CH3CH2CH2CH2OH > CH3CH2CH2OH > CH3CH2OCH3)

500

A cup contains 500.0 g of water.
a) How many moles of water are in the cup?
b) How many hydrogen atoms are in the cup of water?

a. 27.75 mol H₂O

b. 3.34×1025 H atoms


500 g H2O x (1 mol/(2(1)+16 g))

27.75 mol H2O (6.02x1023atom/mol) (2 atoms H/molecule)

500

C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g). You have 10.0 g C3H8 and 40.0 L O2. Assume O₂ is measured at STP. Which reactant limits the reaction, and what mass of CO2 is produced?

limiting reactant: C3H8 produces 29.94 g CO2

10 g C3H8 (mol C3H8/44.095 g) (3 mol CO2/ 1mol C3H8) = 0.68035 mol CO2

40 L O2 (mol O2/22.4 L) (3 mol CO2/ 5 mol O2) = 1.07076 mol CO2

0.68035 mol CO2 (44.0095 g/mol CO2)

500

2 KClO3(s) → 2 KCl(s) + 3 O2(g)

25.0 g KClO3 is fully decomposed. What volume (in L) of O₂ is produced at T = 350.0 K and P = 0.950 atm?

9.25 L O₂

25 g KClO3 (mol/122.55 g) (3 mol O₂/ 2 mol KClO3) = 0.30600 mol O2

V=nRT/P 

(0.30600×0.08206×350.0)/0.950

500

  1. How many liters of CO₂ at 0.950 atm and 25.0 °C are produced by decomposition of 50.0 g CaCO₃? 

CaCO₃ → CaO + CO₂

  1. 12.865 L

  2. 50.0 g CaCO3(1/mol/100.089 g) = 0.49956 mol -> (0.49956(0.08206)(298.15)/0.950 V= nRT/P