To find the total number of neutrons and the total mass of neutrons in 7mg of carbon-14 (14C), we need to follow these steps:
(i) Calculate the total number of neutrons:
Step 1: Determine the atomic mass of carbon-14 (14C).
The atomic mass of carbon-14 is 14 atomic mass units (AMU).
Step 2: Identify the number of protons in carbon-14.
Carbon has 6 protons, so carbon-14 also has 6 protons.
Step 3: Subtract the number of protons (6) from the atomic mass (14).
14 - 6 = 8 neutrons.
Therefore, carbon-14 has 8 neutrons.
(ii) Calculate the total mass of neutrons:
Step 1: Determine the mass of a neutron.
The question states that the mass of a neutron is equal to the mass of a hydrogen atom.
Step 2: Find the mass of a hydrogen atom.
The mass of a hydrogen atom is approximately 1 atomic mass unit (AMU).
Step 3: Calculate the total mass of neutrons.
Multiply the mass of a neutron (1 AMU) by the number of neutrons (8) in carbon-14:
1 AMU * 8 neutrons = 8 AMU.
Therefore, the total mass of the neutrons in 7mg of carbon-14 is 8 atomic mass units (AMU).