find (i) the total no. of neutrons and (ii) the total mass of neutrons in 7mg o^14C. (assume that the mass of a neutron = mass of a hydrogen atom)
In 14g of 14^C,no.of neutrons =8NA
In 1g of 14C,no.of neutrons =8NA/14
1)the total no.of neutrons in 7mg of 14^C= 7/1000×4/7×6×10^20
=24×10^20
2)given mass of a neutron=mass of 1 Hydrogen atom=1 amu
Mass of 24×10^20 neutrons=1×24×10^20×1.6×10^-24 g
=0.0004 g
Are you from resonance?
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).
mols = grams/molar mass
0.007g/14 = ? mols C14 atoms
There are 7 neutrons/atom; therefore,
# mols x 7 = ? mols neutrons.
There are 6.02E23 neutrons for each mol of neutrons; therefore,
mols neutrons x 6.02E23 neutrons/mol = # neutrons.
mass of those neutrons = # neutrons x mass of H atom.