Answer:
Option C. 1
Explanation:
Step 1:
Determination of the Neutron of both isotopes. This is illustrated below.
For isotope y xA:
Mass number = y
Atomic number = x
Neutron =..?
Atomic number = proton number = x
Mass number = Proton + Neutron
y = x + Neutron
Rearrange
Neutron = y – x
For isotope (y + 1) xA:
Mass number = y + 1
Atomic number = x
Neutron =.?
Atomic number = proton number = x
Mass number = Proton + Neutron
y + 1 = x + Neutron
Rearrange
Neutron = y + 1 – x
Step 2:
Determination of the difference between the neutron number of both isotopes. This is illustrated below:
For isotope y xA:
Neutron number = y – x
For isotope (y + 1) xA:
Neutron number = y + 1 – x
Difference in neutron number
=> (y + 1 – x) – (y – x)
=> y + 1 – x – y + x
Rearrange
=> y – y + 1 – x + x
=> 1
Therefore, the difference in the neutron number of both isotopes is 1
Answer:
1.32*10^23 molecules
Explanation:
sucrose formula: C12H22O11
molar mass: 12(12.01)+22(1.01)+11(16.00)=342.34g/mol
75.0 g C12H22O11 * (1 mol C12H22O11)/(342.34g C12H22O11)=0.219 mol C12H22O11
0.219 mol * (6.022*10^23)/mol = 1.32*10^23 molecules (three sig. figures)
Concentration is the number of moles of solute in a fixed volume of solution
Concentration(c) = number of moles of solute(n) / volume of solution (v)
25.0 mL of water is added to 125 mL of a 0.150 M LiOH solution and solution becomes more diluted.
original solution molarity - 0.150 M
number of moles of LiOH in 1 L - 0.150 mol
number of LiOH moles in 0.125 L - 0.150 mol/ L x 0.125 L = 0.01875 mol
when 25.0 mL is added the number of moles of LiOH will remain constant but volume of the solution increases
new volume - 125 mL + 25 mL = 150 mL
therefore new molarity is
c = 0.01875 mol / 0.150 L = 0.125 M
answer is 0.125 M
