Exam

Calculate the ΔG for the following system. Then state if the system is spontaneous or not spontaneous. ΔH = + 25 kJ ΔS = +5.0 J/K T = 23°C

+24 kJ; not spontaneous

Determine the oxidation number of the element that is underlined within the compound. Li2 SiO3

+4

Use the standard enthalpies of formation for the reactants and products to solve for the ΔHrxn for the following reaction. (The ΔHf of Ca(OH)2 is -986.09 kJ/mol and liquid H2O is -285.8 kJ/mol.) Ca(s) + 2H2O(l) Ca(OH)2 (s) + H2(g) ΔHrxn = The reaction is .

-414.4 kJ exothermic

Given the chemical equation, predict the ΔSsystem for this change. O2 (g) O2 (aq)

-ΔS

What is the molarity of an aqueous solution that contains 12.2 grams of SrCl2 dissolved in 2,500 milliliters of solution?

0.031 M

An experiment is conducted using nitrogen monoxide and bromine reacted to form nitrosyl bromide. Calculate Keq for the reaction using the following equation data. [NOBr] = 0.0474 mol/L [NO] = 0.312 mol/L [Br2] = 0.259 mol/L Keq =

0.0891

How many moles are present in 10.5 grams of NaCl?

0.180 mol

Twenty-seven milliliters of an acid with an unknown concentration are titrated with a base that has a concentration of 0.55 M. The indicator changed color when 12.5 milliliters of base were added. What is the concentration of the unknown acid?

0.25 M

How many grams of NaCl are needed in order to make a liter of a 2.00 M NaCl solution?

117g

Choose the amount of carbon atoms that would be present in an alkane that contains 32 hydrogen atoms. C___H32

15

Balance the following equation. Choose "blank" if no coefficient other than 1 is needed. K + H20 H2 + KOH

2 2 blank 2

Calculate the number of molecules present in 3.50 mol FeO2.

2.11 x 1024 molecules

Answer the questions about the following reaction. 4Al(s) + 3O2(g) 2Al2O3 (s) How many molecules of O2 are used in the reaction? How many oxygen atoms are required? How many moles of Al2O3 are formed? What is the mole ratio of Al to O2?

3 6 2 4/3

What would be the pH of an HCl solution if the [H+] = 2.75 x 10-5 moles/liter?

4.56

The specific heat of zinc is 0.39 J/g*°C. How much energy needed to change the temperature of 34g of zinc from 22°C to 57°C. Is the energy absorbed or released?

464.1 J, absorbed

If a chemist wants to make 1.3 L of 0.25 M solution of KOH by diluting a stock solution of 0.675 M KOH, how many milliliters of the stock solution would the chemist need to use?

480 mL

How many significant digits are in 6.3590 x 107 mm?

5

Express the following number in scientific notation.

5.3000 x 10-1

What is the molecular weight (mass) for KOH?

56.10 g/mol

If a sample of iron with a density of 7.80 g/cm3 displaces 75.0 mL of water when placed in a beaker, what is its mass?

585 g

Which of the following is not equal to 63.7 mm?

637 cm

How many atoms are found in 1.56 moles of Na?

9.39 x 1023 atoms

According to periodic trend, which of the following most likely has the highest ionization energy?

Ar

Which of the following shows the proper configuration of a straight chain isomer of hexane?

B

Classify the chemical reaction: Cl2O5 + H2O ⟶ 2HClO3

Combination

Substance A dissolves in water. What can be said about substance A?

It is polar.

Identify the products of the reaction between 2KOH and H2SO4.

K2SO4 and H2O

According to the periodic trend, which of the following is most likely to have the lowest electronegativity?

Li

Which of the following is the correct chemical formula for Na and S?

Na2S

Classify the chemical reaction: 2Al + 3NiSO4 ⟶ Al2(SO4)3 + 3Ni

Single Displacement

Which is NOT an indicator of a chemical change?

State of matter changes.

A(n) _____ is a hydrocarbon in which one or more hydrogen atoms is replaced by a -COOH and a -NH2 group.

amino acid

Balance the reaction which forms ions. Choose "blank" if no coefficient other than 1 is needed. Pb(N03)2(aq) Pb+2 + NO3 -

blank 2

Identify the method of heat transfer taking place in the given situation. A spoon full of sugar is stirred into a cup of hot coffee and the spoon gets warm. The method of heat transfer in this situation is known as:

conduction

According to electronegativity difference, what type of bond are oxygen and hydrogen most likely to form?

covalent

What type of reaction is represented in the following example? 2C2H4O(g) + 5O2 (g) 4CO2 (g) + 4H2O (l) ΔH = -2385 kJ

exothermic

When hydrochloric acid reacts with potassium hydroxide solution, the following reaction occurs. HCl (aq) + KOH (aq) H2O (l) + KCl (aq) The reaction gives off heat energy, so it is an reaction.

exothermic

Testing a hypothesis is called a(n) _____.

experiment

A straight chain hydrocarbon with the formula C6H12 _____.

has a double C-C bond

C3H8 has a boiling point than C2H6.

higher

If two gases react, compressing the gases generally the rate of reaction.

increases

A scientific law _____.

is true all the time

In an exothermic reaction, the products have _____.

less energy than the reactants

A solution has a Pb2+ concentration of 1.9 x 10-3 M, and an F-1 concentration of 3.8 x 10-3 M. The value of Ksp for PbF2 at room temperature is 4 x 10-8. Will this solution form a precipitate? The solubility equilibrium equation is as follows.

no

In the following reaction, is Sb reduced or oxidized? 2Sb (s) + 6H2SO4 (aq) Sb2(SO4)3 + 3SO2 + 6H2O

oxidized

Methane, CH4, is a(n) hydrocarbon.

saturated

Choose whether the process below is spontaneous or not spontaneous. Salt dissolves in water.

spontaneous

Milk of magnesia helps to neutralize stomach acid because it is a _____.

strong base

Identify the main function of carbohydrates.

supply energy to cells

Other than carbon being relatively small, what is another reason that carbon can form so many compounds?

the ability to form four covalent bonds

The number of molecules in 1.0 mole of H2O is _____ as in one mole of O2.

the same

Hydrocarbons that have one or more double or triple bonds are _____.

unsaturated