James June 2019

As the elements in Period 2 of the Periodic Table are considered in order from left to right, which property generally decreases? (1) atomic radius (2) electronegativity (3) ionization energy (4) nuclear charge

(1) atomic radius

Given the equation representing a reversible reaction: CH3COOH(aq) + H2O(l) ⇌ CH3COO-(aq) + H3O+(aq) According to one acid-base theory, the two H donors in the equation are (1) CH3COOH and H2O (2) CH3COOH and H3O+ (3) CH3COO- and H2O (4) CH3COO- and H3O+

(2) CH3COOH and H3O+

Which elements are present in the mixture? (1) G and J (2) G and L (3) M, J, and G (4) M, J, and L

(2) G and L

A student measures the mass and volume of a sample of aluminum at room temperature, and calculates the density of Al to be 2.85 grams per cubic centimeter. Based on Table S, what is the percent error for the student's calculated density of Al? (1) 2.7% (3) 5.6% (2) 5.3% (4) 95%

(3) 5.6%

What is the percent composition by mass of nitrogen in the compound N2H4 (gram-formula mass 32 g/mol)?

(3) 88%

42 Which sample of HCl(aq) reacts at the fastest rate with a 1.0-gram sample of iron filings? (1) 10. mL of 1 M HCl(aq) at 10.°C (2) 10. mL of 1 M HCl(aq) at 25°C (3) 10. mL of 3 M HCl(aq) at 10.°C (4) 10. mL of 3 M HCl(aq) at 25°C

(4) 10. mL of 3 M HCl(aq) at 25°C

Which electron configuration represents an atom of chlorine in an excited state? (1) 2-8-7-2 (2) 2-8-7 (3) 2-8-8 (4) 2-7-8

(4) 2-7-8

43 Given the equation representing a system at equilibrium: N2O4(g) ⇌ 2NO2(g) Which statement describes the concentration of the two gases in this system? (1) The concentration of N2O4(g) must be less than the concentration of NO2(g). (2) The concentration of N2O4(g) must be greater than the concentration of NO2(g). (3) The concentration of N2O4(g) and the concentration of NO2(g) must be equal. (4) The concentration of N2O4(g) and the concentration of NO2(g) must be constant.

(4) The concentration of N2O4(g) and the concentration of NO2(g) must be constant.

Given the equation representing a system at equilibrium: PCl5(g) + energy ⇌ PCl3(g) + Cl2(g) Which change will cause the equilibrium to shift to the right? (1) adding a catalyst (2) adding more PCl3(g) (3) increasing the pressure (4) increasing the temperature

(4) increasing the temperature

Magnesium and calcium have similar chemical properties because their atoms in the ground state have (1) equal numbers of protons and electrons (2) equal numbers of protons and neutrons (3) two electrons in the first shell (4) two electrons in the outermost shell

(4) two electrons in the outermost shell

What is the amount of heat absorbed when the temperature of 75 grams of water increases from 20.°C to 35°C? (1) 1100 J (2) 4700 J (3) 6300 J (4) 11 000 J

2) 4700 J

Given the balanced equation for the reaction of butane and oxygen: 2C4H10 + 13O2 → 8CO2 + 10H2O + energy How many moles of carbon dioxide are produced when 5.0 moles of butane react completely? (1) 5.0 mol (2) 10. mol (3) 20. mol (4) 40. mol

20. mol

Which substance is an Arrhenius base? Choices: HNO3, H2SO3, Ca(OH)2, CH3COOH

Ca(OH)2

Which particle model diagram represents xenon at STP? HINT: XENON IS A GAS!

Choice 1

The molar masses and boiling points at standard pressure for four compounds are given in the table below. (See picture) Which compound has the strongest intermolecular forces? (1) HF (2) HCl (3) HBr (4) HI

HF

Which statement explains why NaBr is classified as a compound?

Na and Br are chemically combined in a fixed proportion

Based on Table I, which compound dissolves in water by an exothermic process? NaCL, NH4Cl, NaOH, NH4NO3

NaOH

Which ion in the ground state has the same electron configuration as an atom of neon in the ground state? (1) Ca+2 (2) Cl-(3) Li+ (4)2

O-2

Using equal masses of reactants, which statement describes the relative amounts of energy released during a chemical reaction and a nuclear reaction?

The nuclear reaction releases more energy than a the chemical reaction.

Which statement describes the components of a mixture?

The proportions can vary.

The effect of a catalyst on a chemical reaction is to provide a new reaction pathway that results in a different

activation energy

Equilibrium can be reached by

both physical and chemical changes

Which nuclear equation represents a spontaneous decay? SEE PICTURE

choice 1

During all chemical reactions, charge, mass and energy are

conserved (THINK CONSERVATION OF MASS AND ENERGY)

The ratio of the mass of U-238 to the mass of Pb-206 can be used to

date geological formations

Graphite and diamond are two forms of solid carbon at STP. These forms have

different molecular structures and different properties

The degree of polarity of a covalent bond between two atoms is determined by calculating the difference in their

electronegativities

As the first five elements in Group 14 are considered in order from top to bottom, there are changes in both the

electronegativity values and atomic radii

Which two terms represent types of chemical formulas?

empirical and structural

In the ground state, an atom of which element has seven valence electrons? Choices: sodium, nitrogen, phosphorous, fluorine

fluorine

During which two processes does a substance release energy?

freezing and condensation

In which type of nuclear reaction do two nuclei combine to produce a heavier nucleus?

fusion

When an F atom becomes an F- ion, the F atom

gains an electron

Which value is defined as the difference between the potential energy of the products and the potential energy of the reactants during a chemical change?

heat of reaction

The mass of an electron is

less than the mass of a neutron

Chemical systems in nature tend to undergo changes toward

lower energy and higher entropy

Which substance can not be broken down by a chemical change?

magnesium (BECAUSE ITS AN ELEMENT)

The diagram below represents a particle traveling through an electric field. What particle remains undeflected when passing through this electric field?

neutron

At STP, which property of a molecular substance is determined by the arrangement of its molecules?

physical state

Which particles are found in the nucleus of an argon atom?

protons and nuetrons

Compared to the energy of an electron in the second shell of an atom of sulfur, the energy of an electron in

the first shell is lower

Which information is sufficient to differentiate a sample of sodium from a sample of silver

the reactivity of each sample with water

Which statement describe the particles of an ideal gas, based on the kinetic molecular theory?

the volume of the particles is considered negligible

Table sugar can be separated from a mixture of table sugar and sand at STP by adding

water, stirring, and filtering