Question 1

What is the average mass, in grams, of one arsenic atom?

Accepted Answer

The average mass of one arsenic atom is given by the atomic mass of Arsenic (As) which is approximately 74.9 atomic mass units (amu). One amu is equal to 1.66 × 10^-24 grams. Therefore, the average mass of one arsenic atom is 74.9 amu × 1.66 × 10^-24 g/amu = 1.24 × 10^-22 g, which is option D.

Question 2

What is the mass of 7.80 * 10¹⁸ carbon atoms?

Accepted Answer

D

Question 3

Boron obtained from borax deposits in Death Valley consists of two isotopes. They are boron-10 and boron-11 with atomic masses of 10.013 amu and 11.009 amu, respectively. The atomic mass of boron is 10.81 amu (see periodic table). Which isotope of boron is more abundant, boron-10 or boron-11?

Accepted Answer

The atomic mass of boron is closer to that of boron-11 (11.009 amu) than to boron-10 (10.013 amu), indicating that boron-11 is more abundant. This is because the average atomic mass reflects the weighted average of the isotopes, weighted by their abundances.

Question 4

The element oxygen consists of three naturally occuring isotopes: ¹⁶O, ¹⁷O, and ¹⁸O. The atomic mass of oxygen is 16.0 amu. What can be implied about the relative abundances of these isotopes?

Accepted Answer

The answer of The element oxygen consists of three naturally...

Question 5

How many silicon atoms are there in 1.00 g of silicon?

Accepted Answer

The answer of How many silicon atoms are there in...

Question 6

An average atom of uranium (U)is approximately how many times heavier than an atom of potassium?

Accepted Answer

The answer of An average atom of uranium (U)is approximately...

Question 7

Calculate the number of moles of xenon in 12.0 g of xenon.

Accepted Answer

The answer of Calculate the number of moles of xenon...

Question 8

Which one of the following does not represent 1.00 mol of the indicated substance?

Accepted Answer

26.0 g Fe is not equivalent to 1.00 mol of Fe (which is 55.8 g Fe). The other choices are all equivalent to 1.00 mol of the indicated substance.

Question 9

Determine the number of moles of aluminum in 96.7 g of Al.

Accepted Answer

To determine the number of moles of aluminum, we need to use the molar mass of Al, which is 26.98 g/mol.

moles of Al = mass of Al / molar mass of Al
moles of Al = 96.7 g / 26.98 g/mol
moles of Al = 3.58 mol

Therefore, the answer is B) 3.58 mol.

Question 10

If 0.274 moles of a substance weighs 62.5 g, what is the molar mass of the substance, in units of g/mol?

Accepted Answer

The answer of If 0.274 moles of a substance weighs...

Question 11

The mass of 1.21 *10²⁰ atoms of sulfur is

Accepted Answer

The answer of The mass of 1.21 *10²⁰ atoms of...

Question 12

An atom of bromine has a mass about four times greater than that of an atom of neon. Which choice makes the correct comparison of the relative numbers of bromine and neon atoms in 1,000 g of each element?

Accepted Answer

The answer of An atom of bromine has a mass...

Question 13

An atom of helium has a mass about four times greater than that of an atom of hydrogen. Which choice makes the correct comparison of the relative numbers of helium and hydrogen atoms in equal masses of the two elements?

Accepted Answer

Since an atom of helium has a mass four times greater than that of the hydrogen atom, we would require one-fourth the number of helium atoms to have an equal mass of the two elements. Therefore, there are about one-fourth as many helium atoms as hydrogen atoms in equal masses of the two elements.

Question 14

The mass of 1.63 * 10²¹ silicon atoms is

Accepted Answer

The answer of The mass of 1.63 * 10²¹ silicon...

Question 15

An atom of bromine has a mass about four times greater than that of an atom of neon. How many grams of neon will contain the same number of atoms as 1,000 g of bromine?

Accepted Answer

The number of atoms in a given amount of substance is determined by Avogadro's number, which is constant for one mole of any substance. Since the mass of bromine is about four times greater than that of neon, to have the same number of atoms, you would need a quarter of the mass of bromine in neon. Therefore, 1,000 g of bromine would have the same number of atoms as 250 g of neon.

Question 16

One mole of iron

Accepted Answer

The atomic mass of iron (Fe) is approximately 55.85 g/mol, and the atomic mass of lead (Pb) is approximately 207.2 g/mol. Therefore, one mole of iron is lighter than one mole of lead, not heavier. Also, one mole of iron weighs approximately 55.85 g, not 77.0 g or 26.0 g. The statement that one mole of iron weighs the same as one mole of lead is incorrect because their atomic masses are different.

Question 17

One nanogram does not seem like a very large number. How many magnesium atoms are there in 1.00 ng of magnesium?

Accepted Answer

The answer of One nanogram does not seem like a...

Question 18

There are two stable isotopes of chlorine: chlorine-35, with a mass of 34.968853 amu; and chlorine-37, with a mass of 36.965903. Given that the average atomic mass of a chlorine atom is 35.45 amu, which of the following statements is true?

Accepted Answer

The answer of There are two stable isotopes of chlorine:...

Question 19

What is the average mass, in grams, of one potassium atom?

Accepted Answer

The answer of What is the average mass, in grams,...

Question 20

What is the average mass, in grams, of one atom of iron?

Accepted Answer

The answer of What is the average mass, in grams,...

Quiz 3: Stoichiometry

What is the average mass, in grams, of one arsenic atom?

What is the mass of 7.80 * 10¹⁸ carbon atoms?

Boron obtained from borax deposits in Death Valley consists of two isotopes. They are boron-10 and boron-11 with atomic masses of 10.013 amu and 11.009 amu, respectively. The atomic mass of boron is 10.81 amu (see periodic table) . Which isotope of boron is more abundant, boron-10 or boron-11?

The element oxygen consists of three naturally occuring isotopes: ¹⁶O, ¹⁷O, and ¹⁸O. The atomic mass of oxygen is 16.0 amu. What can be implied about the relative abundances of these isotopes?

How many silicon atoms are there in 1.00 g of silicon?

An average atom of uranium (U) is approximately how many times heavier than an atom of potassium?

Calculate the number of moles of xenon in 12.0 g of xenon.

Which one of the following does not represent 1.00 mol of the indicated substance?

Determine the number of moles of aluminum in 96.7 g of Al.

If 0.274 moles of a substance weighs 62.5 g, what is the molar mass of the substance, in units of g/mol?

The mass of 1.21 *10²⁰ atoms of sulfur is

An atom of bromine has a mass about four times greater than that of an atom of neon. Which choice makes the correct comparison of the relative numbers of bromine and neon atoms in 1,000 g of each element?

An atom of helium has a mass about four times greater than that of an atom of hydrogen. Which choice makes the correct comparison of the relative numbers of helium and hydrogen atoms in equal masses of the two elements?

The mass of 1.63 * 10²¹ silicon atoms is

An atom of bromine has a mass about four times greater than that of an atom of neon. How many grams of neon will contain the same number of atoms as 1,000 g of bromine?

One mole of iron

One nanogram does not seem like a very large number. How many magnesium atoms are there in 1.00 ng of magnesium?

There are two stable isotopes of chlorine: chlorine-35, with a mass of 34.968853 amu; and chlorine-37, with a mass of 36.965903. Given that the average atomic mass of a chlorine atom is 35.45 amu, which of the following statements is true?

What is the average mass, in grams, of one potassium atom?

What is the average mass, in grams, of one atom of iron?

Quiz 3: Stoichiometry

What is the average mass, in grams, of one arsenic atom?

What is the mass of 7.80 * 1018 carbon atoms?

Boron obtained from borax deposits in Death Valley consists of two isotopes. They are boron-10 and boron-11 with atomic masses of 10.013 amu and 11.009 amu, respectively. The atomic mass of boron is 10.81 amu (see periodic table) . Which isotope of boron is more abundant, boron-10 or boron-11?

The element oxygen consists of three naturally occuring isotopes: 16O, 17O, and 18O. The atomic mass of oxygen is 16.0 amu. What can be implied about the relative abundances of these isotopes?

How many silicon atoms are there in 1.00 g of silicon?

An average atom of uranium (U) is approximately how many times heavier than an atom of potassium?

Calculate the number of moles of xenon in 12.0 g of xenon.

Which one of the following does not represent 1.00 mol of the indicated substance?

Determine the number of moles of aluminum in 96.7 g of Al.

If 0.274 moles of a substance weighs 62.5 g, what is the molar mass of the substance, in units of g/mol?

The mass of 1.21 *1020 atoms of sulfur is

An atom of bromine has a mass about four times greater than that of an atom of neon. Which choice makes the correct comparison of the relative numbers of bromine and neon atoms in 1,000 g of each element?

An atom of helium has a mass about four times greater than that of an atom of hydrogen. Which choice makes the correct comparison of the relative numbers of helium and hydrogen atoms in equal masses of the two elements?

The mass of 1.63 * 1021 silicon atoms is

An atom of bromine has a mass about four times greater than that of an atom of neon. How many grams of neon will contain the same number of atoms as 1,000 g of bromine?

One mole of iron

One nanogram does not seem like a very large number. How many magnesium atoms are there in 1.00 ng of magnesium?

There are two stable isotopes of chlorine: chlorine-35, with a mass of 34.968853 amu; and chlorine-37, with a mass of 36.965903. Given that the average atomic mass of a chlorine atom is 35.45 amu, which of the following statements is true?

What is the average mass, in grams, of one potassium atom?

What is the average mass, in grams, of one atom of iron?

What is the mass of 7.80 * 10¹⁸ carbon atoms?

The element oxygen consists of three naturally occuring isotopes: ¹⁶O, ¹⁷O, and ¹⁸O. The atomic mass of oxygen is 16.0 amu. What can be implied about the relative abundances of these isotopes?

The mass of 1.21 *10²⁰ atoms of sulfur is

The mass of 1.63 * 10²¹ silicon atoms is