Q: What is the de Broglie wavelength of a $$3.32 \times 10$$^{-27}$$\ \mathrm{kg}$$ helium atom moving at $$1.00 \times 10^3$\ \mathrm{m/s}$$? ($$h = 6.626 \times 10$$^{-34}$$\ \mathrm{J\cdot s})$$

$$ 2.00 \times 10^{-10}\ \mathrm{m} $$

Question 1

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture in which the composition is uniform throughout, such as salt dissolved in water.

Question 2

Which statement correctly distinguishes between a scientific law and a scientific theory?

Accepted Answer

A scientific law summarizes a pattern observed in nature, while a scientific theory explains why that pattern occurs.

Question 3

Which experiment provided evidence for the existence of the atomic nucleus?

Accepted Answer

Rutherford's gold foil experiment

Question 4

An atom has 17 protons, 18 neutrons, and 18 electrons. What is its nuclear symbol?

Accepted Answer

$$ ^{35}_{17}\mathrm{Cl}^{-} $$

Question 5

A sample contains 75.78% $$^{35}\mathrm{Cl} ($$mass = 34.969 amu) and 24.22% $$^{37}\mathrm{Cl} ($$mass = 36.966 amu). What is the average atomic mass of chlorine?

Accepted Answer

$$ 35.45\ \mathrm{amu} $$

Question 6

Which of the following is an extensive property?

Accepted Answer

Mass

Question 7

A student measures the mass of a sample as 0.02030 g. How many significant figures are in this measurement?

Accepted Answer

4

Question 8

How many oxygen atoms are present in 18.0 g of water ($$\mathrm{H}_2\mathrm{O}$$)? (Molar mass of $$\mathrm{H}_2\mathrm{O} = 18.0 g/$$mol, Avogadro's number = $$6.022 	imes 10$$^{23}$$)

Accepted Answer

$$ 6.022 	imes 10^{23} $$

Question 9

Which of the following correctly describes the photoelectric effect?

Accepted Answer

Electrons are ejected from a metal surface when it is exposed to light of sufficient frequency.

Question 10

What is the de Broglie wavelength of a $$3.32 	imes 10$$^{-27}$$\ \mathrm{kg}$$ helium atom moving at $$1.00 	imes 10^3$\ \mathrm{m/s}$$? ($$h = 6.626 	imes 10$$^{-34}$$\ \mathrm{J\cdot s})$$

Accepted Answer

$$ 2.00 	imes 10^{-10}\ \mathrm{m} $$

Question 11

Which set of quantum numbers is not allowed for an electron in an atom?

Accepted Answer

$$ n = 2,\ l = 2,\ m_l = 0,\ m_s = +\frac{1}{2} $$

Question 12

Which element has the electron configuration $$[\mathrm{Ne}]\ 3s^2$\ 3p^5$?

Accepted Answer

Chlorine

Question 13

Which of the following ions is isoelectronic with neon?

Accepted Answer

$$ \mathrm{F}^{-} $$

Question 14

Which of the following statements about periodic trends is correct?

Accepted Answer

Atomic radius decreases across a period from left to right.

Question 15

What is the correct formula for the ionic compound formed between magnesium and nitrogen?

Accepted Answer

$$ \mathrm{Mg}_3\mathrm{N}_2 $$

Question 16

A compound is found to contain 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is its empirical formula?

Accepted Answer

$$ \mathrm{CH}_2\mathrm{O} $$

Question 17

Which of the following molecules is nonpolar, despite having polar bonds?

Accepted Answer

$$ \mathrm{CO}_2 $$

Question 18

Which of the following best explains why water has a higher boiling point than methane?

Accepted Answer

Water molecules form hydrogen bonds, which are stronger than the London dispersion forces in methane.

Question 19

A 2.00 L solution contains 0.50 mol of NaCl. What is the molarity of the solution?

Accepted Answer

$$ 0.25\ \mathrm{M} $$

University Chemistry I: Comprehensive Study Guide and Learning Objectives

Guida di studio - Domande di pratica

Study guide - Flashcard