Q: A sample of copper wire has a diameter of $$0.9750 mm $$and a length of $$3.60 m. If $$the density of copper is $$8.96 g/cm$^3$$, how many copper atoms are present? ($$r = \frac{d}{2}$$, $$V = \pi r^2$ h$$; atomic mass of Cu = $$63.55 g/$$mol)

$$3.05 \times 10$$^{23}$$ atoms

Question 1

Which subatomic particle is responsible for the chemical identity of an element?

Accepted Answer

Proton

Question 2

A neutral atom of calcium-43 has how many protons, neutrons, and electrons?

Accepted Answer

20 protons, 23 neutrons, 20 electrons

Question 3

Which of the following ions is isoelectronic with neon ($$Ne$$)?

Accepted Answer

$$F^-$$

Question 4

Which element in the first column of the periodic table has the greatest atomic mass?

Accepted Answer

Cesium ($$Cs)$$

Question 5

Calculate the atomic mass of an element with two isotopes: 60.0% abundance of 10.0 amu and 40.0% abundance of 12.0 amu.

Accepted Answer

$$10.8$$ amu

Question 6

Which of the following elements is a metalloid?

Accepted Answer

Silicon ($$Si)$$

Question 7

A sample of copper wire has a diameter of $$0.9750 mm $$and a length of $$3.60 m. If $$the density of copper is $$8.96 g/cm$^3$$, how many copper atoms are present? ($$r = \frac{d}{2}$$, $$V = \pi r^2$ h$$; atomic mass of Cu = $$63.55 g/$$mol)

Accepted Answer

$$3.05 	imes 10$$^{23}$$ atoms

Question 8

Which of the following is NOT a component of Dalton's Atomic Theory?

Accepted Answer

Atoms can be divided into protons, neutrons, and electrons.

Question 9

Which element is a representative element in the 2nd Period that is a solid at room temperature?

Accepted Answer

Boron ($$B)$$

Question 10

If the charge and mass of one proton is $$1.6022 	imes 10$$^{-19}$$ C and 1.673$$ 	imes $$10^{-27} g $$respectively, what is the charge of $$7.5 	imes 10$$^{18}$$ protons?

Accepted Answer

$$1.20 C$$

Question 11

Which of the following elements is most likely to form a $$2+$$ cation?

Accepted Answer

Magnesium ($$Mg)$$

Question 12

What is the molar mass of $$Ca(H_2PO_4)_2$$?

Accepted Answer

$$234.1 g/$$mol

Question 13

A sample of sodium chloride ($$NaCl) $$contains $$71.1 kg. $$What is the number of formula units present? ($$NaCl$$ molar mass = $$58.44 g/$$mol, $$N_A = 6.022 	imes 10$$^{23}$$)

Accepted Answer

$$7.33 	imes 10$$^{26}$$

Question 14

Which of the following best illustrates the Law of Multiple Proportions?

Accepted Answer

Nitrogen forms two oxides: $$NO$$ and $$NO_2$$, with mass ratios of oxygen to nitrogen in a ratio of small whole numbers.

Question 15

Which experiment led to the discovery of the nucleus as a small, dense, positively charged region within the atom?

Accepted Answer

Rutherford Gold Foil Experiment

Question 16

Which of the following elements is a transition metal in the 4th Period with similar chemical properties to copper ($$Cu$$)?

Accepted Answer

Nickel ($$Ni)$$

Question 17

Which of the following compounds is a homonuclear diatomic molecule?

Accepted Answer

Hydrogen ($$H_2)$$

Question 18

If a sample of water has a mass of $$1.50 	imes 10^4$ $$	ext{g}$$, how many molecules of water are present? (M$$_{H_2O} = 18.02$$ g/mol, N_A = 6.022$$ 	imes $$10^{23})$$

Accepted Answer

$$5.01 	imes 10$$^{26}$$

Question 19

Which of the following statements is TRUE regarding the forces in the nucleus?

Accepted Answer

Nuclear force holds protons and neutrons together, overcoming electrostatic repulsion.

Question 20

Which of the following elements is a nonmetal that is a halogen?

Accepted Answer

Chlorine ($$Cl)$$

Atoms & Elements: General Chemistry Study Notes

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