Literally everything from gen chem

2045: exams and concepts; 2046 ps and quizzes

What is the molar mass of K2SO4

174 g/mol

Which of following are incorrectly paired?

Samarium, Sm

How many milliliters are containers in 2.5 liters?

2.5 × 10^3 mL

What is the mass of an aluminum atom?

4.48 × 10^-23 g

Which element is from the halogens?

F

How many molecules are in 46.0 g of C2H6O?

6.02 X 10^ 23

Which is a weak electrolyte?

HF

Consider the reaction:

CH4 + 2O₂ → CO₂ + 2H₂O

What mass of CO2 is formed b the reaction of 16.0 g of O₂ with an excess of CH₄?

11.0 g

What salt forms between the ions ammonium and phosphate?

(NH4)3PO4

The correct reaction coefficient on NaCl when following reaction is balanced is:

Na3PO4 + CaCl2 → Ca3(PO4)2 +NaCl

6

What is the name of H2CO3?

carbonic acid

Hydrogen reacts with oxygen as follows:

2H2 + O2 → 2H2O

When 4.00 g of H2 reacts with 24.0g of O2, which statement applies?

27.0g of water are formed

the prefix for 10³ is:

kilo

Determine the value both in scientific notation as well as the number of sig figs:

14.72 + 3.6 + 8.245=?

2.66 × 10^ 1, three sig figs

An analysis of a hydrocarbon revealed that it contained 7.7% hydrogen and 92.3% carbon by weight. A mass spectra revealed that its molecular weight was 65 amu. The correct molecular formula is:

C5H5

Correct name for HBrO3 is:

bromic acid

Which elements forms a stable +2 cation:

Ca

at 25 degrees C, one milliliter of gold had a mass of 19.3 grams. How many liters of gold are required to have a mass of 250 kg of gold?

12.9 L

When potassium iodide and silver nitrate react in an aqueous solution, which of the following terms will be present in the balanced net ionic equation?

AgI(s)

Na2CO3 + CaCl2 → CaCO3 + 2NaCl

What mass of NaCO3 (MW=106 g/mol) is needed to form 23.4g of NaCl (MW=58.44 g/mol)

21.2 g

All of the following are postulates of Bohrs’s Atomic Theory except:

electrons spin about an axis

The electron configuration of V³+

[Ar] 3d^ 2

The following electronic transition would involve the absorption of light with the shortest wavelength:

n=2 → n=5

Give the number of protons, neutrons, and electrons in an atom of the isotope 79 Br.

35p; 44n; 35e

Which is the electron configuration of S in its ground state?

1s² 2s² 2p⁶ 3s^2 3p^4

Which elements has the most negative (most exothermic) electron affinity?

S

The average atomic mass of an unknown element if the isotopic of 62Y and 64Y are 48.0% and 52.0%, respectively.

63.0

which form of electromagnetic radiation has the shortest wavelength?

x-rays

The following set of quantum numbers represents the “last“ electron added to complete the ground state electron configuration of an element according to the Aufbau Principle, which could be the symbol for the element?

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

Ti

The following properties can be explained by the particle nature of light except:

diffraction

A given set of d orbitals consist of how many orbitals?

5

How many unpaired electrons are present in the ground state sulfur atom?

2

For a principle quantum number of 2, the max number of electrons that can occupy the electronic shell is:

8

which element had the smallest atomic radius

O

F ; Ba ; S ; B ; Ge

The element with the highest ionization energy is ?, and the element that is the most metallic is?.

F, Ba

F ; Sr ; S ; Li ; Al

The element that has the largest radius is ?, and the element that forms a stable -1 anion is ?.

Sr, F

Which of the following statements is false?

A) Ionization energy generally increases across a period left to right.

B) Electronegativity values generally decrease from top to bottom within a group.

C) The alkali metals (group 1) have the highest ionization energies within their periods.

D) Noble gases typically have the largest ionization energies within a period.

C

Determine the molecular and electronic geometry of ClX4+, where X is a halogen.

Electronic: trigonal bipyramid, Molecular: seesaw

Which molecule has the shortest bond length?

BF

How many resonance structures does O3 have?

2

A molecule that has the most ionic bonds:

Ba-F

Consider the BeCl2 molecule. Which statement about this molecule is false?

The molecule is polar

Which is the most electronegative

Cl

A compound that has the largest lattice energy:

MgO

Which molecule contains the most polar bonds? (electronegativities: C=2.5, F=4.0, Cl=3.0, Br=2.8, I=2.5)

CF4

The lattice energy of an ionic compound may be determined from the following info except:

heat of combustion

based on periodic trends, which covalent bonds shows the correct partial charge distribution?

δ+ I-F δ-

when u add 73 and 38.617 the sum will have ? sig figs

3

Chromium (III) sulfate had the formula

Cr2(SO4)3

What is the empirical formula of a compound composed of 18.9% hydrogen and 81.1% boron (by weight)

B2H5

Solute

The substance that is dissolved in a solution (e.g., salt in saltwater).

Solvent

The substance that dissolves the solute (e.g., water in saltwater).

Solutions

one compound (solute) is dissolved in another (solvent)

aqueous solution

when the solvent is water

electrolytes

substance which dissolves in water to give an electrically conducting solution

solubility

the amount of a substance that dissolves in a given quantity of solvent

saturated solution

solvent holds as much solute as is possible at that temperature

unsaturated solution

less than the maximum amount of solute for that temperature is dissolved in the solvent

supersaturated solution

solvent holds more solute than is normally possible at that temperature

miscible

when two liquids create a homogenous mixture

immiscible

when two liquids create a heterogeneous mixture

the 4 conditions that determine solubility/miscibility

intermolecular forces, entropy change, temperature, pressure

Solvation

the process where solute particles (ions or molecules) become surrounded and stabilized by solvent molecules

What does each variable mean in Henry’s Law: S_g = kP_g

S_g: the solubility of the gas; k: Henry’s law constant for that gas in that solvent; Pg: The partial pressure of the gas above the liquid

percent mass

Mass % of A = (mass of A in solution/ total mass of solution) x 100

mol fraction

XA = moles of A/ total moles in solution

molarity

M = mol of solute/ L of solution

molality

m = mol of solute/ kg of solvent

Units to express solubility

g/L, mol/L, mol/kg

factors affecting solubility:

temperature, pressure, Henry’s law, molecular size and shape, polarity

grams to moles

moles= mass (grams)/ molar mass (g/mol)

What does each variable mean in Raoult’s law: P_solvent= X_solvent x P°_solvent

Where, Xsolvent is the mole fraction of the solvent and P0solvent is the normal vapor pressure of pure solvent at that temperature.

Vapor pressure of a solution is ? than that of the pure solvent.

LOWER

Positive and negative deviations, what intermolecular forces leads to each?

For a positive deviation, the vapor pressure is greater than expected.

For a negative deviation, the vapor pressure is lower than would be expected

Define colligative properties

Properties of solutions that depend only on the NUMBER of solute particles present, not on the identity of the solute particles.

List the 4 colligative properties

vapor pressure lowering, boiling point elevation, melting point depression, osmotic pressure

Give formulas for ΔTb and ΔTf

ΔT_b =__

ΔT_f =__

What concentration units are used in the above formulas?

DTb = Kb x m; DTf = Kf x m; C, molal, and C/mol

Are the ΔT values to be added or subtracted?

Boiling point: ADDED

Freezing point: SUBTRACTED

Which of the following solutions would not be expected to exist?

NaCl in water

MgCl2 in CCl4

Methanol, CH3OH, in water

Pentane, CsH12, in CCl4

Methanol, CH3OH, in water

Does molarity or molality change with temperature?

molarity

Solubility of a gas increases as ? and ? increases, and decreases as ? is increased

pressure and size, temperature

Physical properties that depend on the ? but not the ? of solute particles in a given amount of solvent are called colligative properties.

number ; kind

Which of these aqueous solutions would be expected to have the lowest freezing point energy?

0.100 m KCl

0.200 m CH3OH

0.100 m NaOH

0.075 m K2SO4

0.075 m K2SO4

The Tyndall effect describes ?

the scattering of light by colloidal particles

Which one of the following statements about soaps and soap molecules is false?

• They are often sodium salts of long chain fatty acids.

• The hydrophilic end of a soap molecule is attracted by grease.

• They have a hydrophobic end.

• They have a polar end.

The hydrophilic end of a soap molecule is attracted by grease.

Which statement is incorrect?

• The Law of Conservation of Energy is another statement of the First Law of Thermodynamics.

• The energy of the universe is constantly increasing.

• Energy is the capacity to do work or to transfer heat.

• Potential energy is the energy that a system possesses by virtue of its position or composition.

The energy of the universe is constantly increasing.

Which term is not correctly matched?

• universe / system plus surroundings

• exothermic / energy is released

• endothermic / energy is absorbed

• state function / property dependent on how the process takes place

state function / property dependent on how the process takes place

Which statement concerning sign conventions for DE = q + w is false?

• For heat absorbed by the system, q is positive.

• For work done by the system, w is negative.

• When energy is released by the reacting system, DE is negative.

• If DE is positive, products are at a lower energy than reactants.

If DE is positive, products are at a lower energy than reactants.

Lattice Energy

how much energy you need to break a bond

hydration energy

Energy released when water molecules surround ions, like salt, as they dissolve

State Raoult’s law and the equation: P(solution) = ________*_________

The vapor pressure of a solvent in an ideal solution is directly proportional to its mole fraction in the solution. Xsolvent x P0solvent

vapor pressure ? as temperature increases, and ? as the strength of the intermolecular forces increases.

increases; decreases

as vapor pressure increases, boiling point ?

decreases

For an ideal mixture of 2 liquids, the total vapor pressure in terms of the mol fractions and partial pressures is expressed as

XA x P0A + XB x P0B

A positive deviation from Raoult’s law implies that

o the vapor pressure of the solution is ? than predicted by ideal

behavior

o the boiling point of the solution is ? than predicted by ideal behavior

o the intermolecular forces in the solution is ? than that of the

individual solvents.

greater; lower; weaker

A negative deviation from Raoult’s law implies that

o the vapor pressure of the solution is ? than predicted by ideal

behavior

o the boiling point of the solution is ? than predicted by ideal behavior

o the intermolecular forces in the solution is ? than that of the

individual solvents.

lower; higher; stronger

define reaction rate

Change in concentration of a reactant or

product per unit time

Name four factors which affect the rate of a chemical reaction

temperature, surface area, concentration, catalysts

For the chemical reaction F → G, the initial concentration of F is 2.7 M and its concentration after 2.0 hours is 1.3 M. What is the average rate of this reaction?

-0.7 M/hr

What happens to the rate of the reaction as

the reaction progresses and why?

The rate decreases because as time progresses, the more the two reactants become one.