chemistry final exam

How many unpaired electrons are found in a ground state atom of Se?

2 -

Which one of the following has the largest lattice energy? A) NaBr B) KI C) AlCl₃ D) Na₂O

C) AlCl₃

Write the chemical formula for iron(III) oxide

Fe2O3

Balance the following chemical equation (if necessary): MnO₂(s) + HCl(aq) → MnCl₂(aq) + H₂O(l) + Cl₂(g)

MnO₂(s) + 4HCl(aq) → MnCl₂(aq) + 2H₂O(l) + Cl₂(g)

Predict the chemical formula for the ionic compound formed by the elements Sr and Cl

SrCl2

What is the correct IUPAC name for IrBr₄?

iridium (IV) bromide

Convert 7.6 cm³ to m³?

- 7.6 cm^3 * 1 m^3/(100)^3 = 7.6 x 10^-6

What is the mass percentage of Na in NaBr?

22.990 + 79.904 = 102.894 22.990/102.894 = 22.34 %

If n = 4, what is the maximum allowed value for ℓ?

3 - According to the rules governing acceptable quantum numbers, the value for ℓ can only be as high as n-1. If n = 2, the maximum value for ℓ is 1.

How many protons (p) and electrons (e) are found in a Se²⁻ ion? A) 34 p, 36 e B) 34 p, 32 e C) 32 p, 34 e D) 36 p, 34 e E) 34 p, 34 e

A) 34 p, 36 e - Se has an atomic number of 34, so it contains 34 protons. The neutral atom would have 34 electrons, but because the ion has a -2 charge, this indicates that there are two additional electrons.

Classify the following compounds as ionic or covalent: OF₂, CuO, SeO₂. A) Covalent, ionic, covalent. B) Ionic, covalent, ionic. C) Covalent, covalent, ionic. D) Ionic, ionic, covalent.

A) Covalent, ionic, covalent. - Ionic bonds occur between a metal and a nonmetal. Covalent bonds occur between two nonmetals.

Which of the following is the electron configuration for Ba? A) [Xe]6s² B) [Rn]6s² C) [Xe]6s¹ D) [Xe]7s² E) [Rn]7s²

A) [Xe]6s²

An electron is shown to occupy a d orbital. Which of the following sets of quantum numbers can describe this electron? A) n = 3, ℓ = 2, mℓ = -2 B) n = 4, ℓ = 1, mℓ = 2 C) n = 5, ℓ = 1, mℓ = 0 D) n = 3, ℓ = 1, mℓ = -1 E) n = 4, ℓ = 3, mℓ = -3

A) n = 3, ℓ = 2, mℓ = -2 - A d orbital is represented by the quantum number ℓ = 2 ( s = 0, p = 1, d = 2, f = 3). The only option that meets this criterion is the set n = 3, ℓ = 2, mℓ = -2.

Write the chemical formula for aluminum fluoride?

AlF3

The ground state electron configuration of an Al atom is A)1s²2s²2p⁶3s²3d¹ B) 1s²2s²2p⁶3s²3p¹ C) 1s²2s²2p⁶3s²3p⁶4s²4p¹ D) 1s²2s²2p⁶3s²3p² E)1s²2s²2p¹

B) 1s²2s²2p⁶3s²3p¹

What is Standard Temperature and Pressure (STP)? A) 298.15 K and 1.00 atm B) 273.15 K and 1.00 atm C) 273.15 K and 0.00 atm

B) 273.15 K and 1.00 atm

Which of the following reactions is a double displacement reaction? A) HCl (g) → H₂ (g) + Cl₂ (g) B) HCl (aq) + NaOH (aq) → H₂O (l) + NaCl (aq) C) Mg (s) + 2HCl (aq) → MgCl₂ (aq) + H₂ (g) D) HCl (g) + C₅H₁₀ (g) →C₅H₁₁Cl (g)

B) HCl (aq) + NaOH (aq) → H₂O (l) + NaCl (aq)

Which of the following is a physical change? A) rusting of a nail B) tearing a piece of paper C) cooking an egg D) burning wood

B) tearing a piece of paper

Determine the number of valence electrons in NH₂OH and then draw the corresponding Lewis structure. A) 16 B) 14 C) 13 D) 10 E) 15

B. 14

Which of the following elements would be chemically similar to calcium (Ca)? A) K B) Sr C) Sc D) S E) Ga

B. Sr - Elements that are in the same family (column) on the periodic table are chemically similar. Sr is in the same family as Ca.

A molecule has an empirical formula of CH, and its molar mass is known to be 26 g/mol. What is its molecular formula? A) CH B) CH₂ C) C₂H₂ D) C₂H E) C₃H₃

C) C₂H₂ - An empirical formula shows the simplest ratio of each element to one another. One carbon atom and one hydrogen atom, CH, have a relative mass of 13 g/mol. If the molar mass of a molecule is 26 g/mol, this would have two carbon atoms and two hydrogen atoms, giving the formula C₂H₂.

Which one of the following can be classified as a strong electrolyte? A) C₆H₁₂O₆ B) CH₃OH C) NH₄NO₃ D) HC₂H₃O₂ E) H₂O

C) NH₄NO₃ - NH₄NO₃ dissolves in water and completely dissociates into ammonium ions and nitrate ions. Therefore it is classified as a strong electrolyte.

Which of the following ions has the electron configuration 1s²2s²2p⁶? A) Mg⁺ B) N²⁻ C) N³⁻ D) O⁻ E) F⁺

C) N³⁻

Which of the following pairs represent isotopes? A) ²⁸Si and ²⁸Si⁴⁺ B) ²⁸Si and ²⁸Al C) ²⁸Si and ²⁹Si D) ²⁸Si and ²⁸Si⁴⁻ E) ²⁸Si⁴⁺ and ²⁸Al³⁺

C) ²⁸Si and ²⁹Si - Isotopes are forms of the same element that differ in the number of neutrons but contain the same number of protons.

Based on their positions in the periodic table, which of the following bonds is the most polar? A) C - O B) C - N C) C - B D) C - F

D) C - F - Polar bonds occur between two nonmetals and have a difference in electronegativities of the atoms. The further apart two atoms are in the same period, the greater the polarity of the bond.

Which one of the following gases would be expected to have the highest speed if all the gases were at the same temperature? A) O₂ B) N₂ C) F₂ D) H₂

D) H₂ - The root mean square speed is represented by this equation: rootmeansquarespeed=√3RTMrootmeansquarespeed=3RTM. Hydrogen gas has the smallest molar mass of this set and would have the fastest speed.

A compound containing Na, C, and O is found to have 1.06 mol Na, 0.528 mol C, and 1.59 mol O. What is the empirical formula of the compound? A) NaCO B) Na₂CO C) Na₂CO₂ D) Na₂CO₃

D) Na₂CO₃ - An empirical formula shows the ratio of each element to one another in the formula unit or molecule. The given moles show that there are twice as many moles of Na as moles of C and that there are three times as many moles of O as moles of C. This yields Na₂CO₃.

Which of the following elements is the most electropositive? A) F B) Cl C) O D) P E) S

D) P - increases going down and to the left

Rank the following atoms in order of increasing first ionization energies (i.e., lowest to highest): Rb, F, Mg, B, N. A) F < N < B < Mg < Rb B) Rb < Mg < F < N < B C) Mg < Rb < F < N < B D) Rb < Mg < B < N < F E) Rb > B > N > F > Mg

D) Rb < Mg < B < N < F - In general, first ionization energy decreases down a group and increases across a period.

Red light has a _____ frequency and a _____ wavelength than ultraviolet rays. A) higher, shorter B) higher, longer C) lower, lower D) lower, longer E) lower, shorter

D. lower, longer

Which of the following transition metals would be expected to have the smallest atomic radius? A) Yttrium (Y) B) Zirconium (Zr) C) Niobium (Nb) D) Technetium (Tc) E) Ruthenium (Ru)

E) Ruthenium (Ru) - Atomic radius generally decreases across a row, so you need to choose an element further to the right of Y.

Perform this mathematical operation and express the answer to the correct number of significant figures: 0.085631 × 1.32 A) 0.113 B) 0.1130 C) 1.41 D) 1.406

a. 0.113

Grape juice is an example of a(n) a. element b. compound c. homogeneous mixture d. heterogeneous mixture

c. homogeneous mixture