Question 1

Question

Question 1
A)What information is needed to calculate the average atomic mass of an element?(1 point)
Responses

the charge on each isotope
the charge on each isotope

the total amount of the element in the sample or in nature
the total amount of the element in the sample or in nature

the relative abundance of its isotopes
the relative abundance of its isotopes

the number of protons in each isotope
the number of protons in each isotope
Question 2
A)Calculate the average atomic mass of a sample of a mixture of argon (Ar). The mixture is 90% argon-36 and 10% argon-38. Argon-36 has an atomic mass of 35.968 amu. Argon-38 has an atomic mass of 37.962 amu.  (1 point)
Responses

36.167 amu
36.167 amu

37.763 amu
37.763 amu

39.948 amu
39.948 amu

3616.74 amu
3616.74 amu
Question 3
A)
A student wants to calculate the average atomic mass of neon in nature. Information about neon is in the table below.

Isotopes in Nature	Atomic Mass (amu)	Natural Abundance (%)
neon-20	19.992	90.48
neon-21	20.993	.27
neon-22	21.991	9.25
Which of the following is a correct way for the student to set up the calculation?

(1 point)
Responses

(19.992 amu×.0027)+(20.993 amu ×.9048)+(21.991 amu ×.0925)
(19.992 amu×.0027)+(20.993 amu ×.9048)+(21.991 amu ×.0925)

(19.992 amu×.9048)+(20.993 amu ×.0027)
(19.992 amu×.9048)+(20.993 amu ×.0027)

(19.992 amu×.9048)+(20.993 amu ×.0027)+(21.991 amu ×.0925)
(19.992 amu×.9048)+(20.993 amu ×.0027)+(21.991 amu ×.0925)

(19.992 amu×.9048)×(20.993 amu ×.0027)×(21.991 amu ×.0925)
(19.992 amu×.9048)×(20.993 amu ×.0027)×(21.991 amu ×.0925)
Question 4
A)There are three stable forms of neon: neon-20, neon-21, and neon-22. Which statement is true?(1 point)
Responses

Their atomic masses differ.
Their atomic masses differ.

The number of neutrons are the same.
The number of neutrons are the same.

Their number of protons differ.
Their number of protons differ.

They are radioactive, like all isotopes.
They are radioactive, like all isotopes.
Question 5
A)Beryllium has an atomic number of 4. How many neutrons does the isotope beryllium-9 have?(1 point)
Responses

5
5

4
4

13
13

9
9

GPT-4o mini · Accepted Answer

Here are the answers to your questions:

Question 1
A) What information is needed to calculate the average atomic mass of an element?
Answer: the relative abundance of its isotopes

Question 2
A) Calculate the average atomic mass of a sample of a mixture of argon (Ar). The mixture is 90% argon-36 and 10% argon-38. Argon-36 has an atomic mass of 35.968 amu. Argon-38 has an atomic mass of 37.962 amu.
Average Atomic Mass Calculation:
(0.90 × 35.968 amu) + (0.10 × 37.962 amu)
= 32.3712 amu + 3.7962 amu
= 36.1674 amu

Answer: 36.167 amu

Question 3
A) A student wants to calculate the average atomic mass of neon in nature. Information about neon is in the table below.
Which of the following is a correct way for the student to set up the calculation?
Answer: (19.992 amu×0.9048)+(20.993 amu ×0.0027)+(21.991 amu ×0.0925)

Question 4
A) There are three stable forms of neon: neon-20, neon-21, and neon-22. Which statement is true?
Answer: Their atomic masses differ.

Question 5
A) Beryllium has an atomic number of 4. How many neutrons does the isotope beryllium-9 have?
Isotope Calculation:
Beryllium has 4 protons (atomic number), and the mass number of beryllium-9 is 9.
Number of neutrons = Mass number - Atomic number = 9 - 4 = 5

Answer: 5