Biology Forums - Study Force

An aluminum foil 0.10 mm thick has how many aluminum atoms per square cm? (The density of aluminum is 2.7  103 kg/m3 and the atomic mass of aluminum is 27.)
 
  A) 6  1017
  B) 6  1020
  C) 6  1024
  D) 6  109
  E) 6  1030

Question 2

If a nucleus had a diameter of 8.0  10-15 m, what would its mass be in atomic mass units?
 
  A) 7
  B) 296
  C) 37
  D) 64
  E) 128

Question 3

What is the density of the nucleus of 90Sr?
 
  A) greater than 3  1020 kg/m3
  B) 90 kg/m3
  C) 2.1  1019 kg/m3
  D) 2.0  1015 kg/m3
  E) 2.3  1017 kg/m3

Question 4

Heavy-water molecules have a mass number of
 
  A) 18.
  B) 3.
  C) 12.
  D) 10.
  E) 20.

Question 5

If an element of atomic number 15 has an isotope of mass number 32
 
  A) the number of neutrons in the nucleus is 15.
  B) the number of neutrons in the nucleus is 17.
  C) the number of protons in the nucleus is 17.
  D) the number of nucleons in the nucleus is 15.
  E) the number of protons in the nucleus is 32.

Question 6

How many protons are there in the carbon-14 nucleus?
 
  A) 8
  B) 14
  C) 6
  D) 1
  E) none

Question 7

The symbol for a certain isotope of strontium is Sr. What is the mass number of this isotope?
 
  A) 38
  B) 52
  C) 88
  D) 90
  E) 128

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Thanks for your help <3