Question 1

Which of the following best describes a compound?

Accepted Answer

A substance composed of two or more chemical elements held together by chemical bonds.

Question 2

Which scientist is credited with the discovery of the neutron?

Accepted Answer

James Chadwick

Question 3

What is the molar mass of carbon dioxide ($$CO_2$$)?

Accepted Answer

$$44\ \mathrm{g/mol}$$

Question 4

Which of the following mixtures is homogeneous?

Accepted Answer

Lemonade

Question 5

Which quantum number describes the shape of an atomic orbital?

Accepted Answer

Azimuthal quantum number ($$\ell)$$

Question 6

A sample contains $$3.01 	imes 10$$^{23}$$ molecules of H_2O$. How many moles of water does this represent?

Accepted Answer

$$0.5$$ moles

Question 7

Which of the following statements about ionic bonds is correct?

Accepted Answer

They are formed by transferring electrons from a metal to a nonmetal.

Question 8

What is the correct electron configuration for sodium ($$Na$$, atomic number 11)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^1$$

Question 9

Which property increases as you move from left to right across a period in the periodic table?

Accepted Answer

Electronegativity

Question 10

A reaction is carried out with $$100\ \mathrm{g} of$$ $$Na$$ and $$100\ \mathrm{g} of$$ $$Cl_2. $$The balanced equation is $$2Na(s) + Cl_2$(g) \rightarrow 2NaCl(s). $$What is the limiting reagent?

Accepted Answer

$$Cl_2$$

Question 11

Which of the following intermolecular forces is present in all substances, but is the only one present in non-polar molecules?

Accepted Answer

Induced dipole-induced dipole (London dispersion)

Question 12

Which of the following best explains why water has a higher boiling point than methane ($$CH_4$$)?

Accepted Answer

Water has stronger hydrogen bonds between molecules.

Question 13

What is the formal charge on the nitrogen atom in the following Lewis structure of $$NO_2$$? (Assume one single and one double bond to oxygen, and one lone pair on nitrogen.)

Accepted Answer

$$+1$$

Question 14

Which of the following is a combustion reaction?

Accepted Answer

$$CH_4(g) + 2O_2(g$$) \rightarrow $$CO_2(g) + 2H_2O(g$$) + \Delta$$

Question 15

Which of the following best describes the geometry of $$SF_6$$ according to VSEPR theory?

Accepted Answer

Octahedral

Question 16

A gas occupies $$10.0\ \mathrm{L} at$$ $$2.0\ \mathrm{atm}$$ and $$300\ \mathrm{K}. $$What will be its volume at $$1.0\ \mathrm{atm}$$ and $$300\ \mathrm{K}$$, assuming ideal behavior?

Accepted Answer

$$20.0\ \mathrm{L}$$

Question 17

Which of the following is NOT a property of gases?

Accepted Answer

They have a definite shape and volume.

Question 18

Which of the following statements about the periodic table is correct?

Accepted Answer

Elements in the same group have the same number of valence electrons.

Question 19

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule consists of two or more atoms bonded together, while a compound consists of two or more different elements bonded together.

Question 20

Which of the following is the correct formula for calculating percent yield in a chemical reaction?

Accepted Answer

$$\frac{	ext{Experimental yield}}{	ext{Theoretical yield}} 	imes 100$$

Foundations of Chemistry: Atoms, Elements, Compounds, and Chemical Reactions

Guida di studio - Domande di pratica

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