Answer:
0.43×10²³ atoms
Explanation:
Given data:
Mass of LiBrO₂ = 4.28 g
Number of atoms of oxygen = ?
Solution:
Number of moles = mass/molar mass
Number of moles = 4.28 g/ 118.84 g/mol
Number of moles = 0.036 mol
We can see 1 mole of LiBrO₂ contain 2 mole of oxygen atm.
0.036 mol × 2 = 0.072 mol
1 mole contain 6.022×10²³ atoms
0.072 mol × 6.022×10²³ atoms / 1mol
0.43×10²³ atoms
Isotopes have the same atomic number or same number Protons, but different mass number or neutrons.
You can say atomic number or protons.
22 neutrons 20 protons
atomic number 20 and a mass number 40
Atomic number 20 and mass # 42
Answer:
D
Explanation:
PV =nRT
So V and T are inversely proportional
Answer:
1. 0.22 mol/dm³
2. 0.23 mol/dm³
Explanation:
Molarity: This can be defined as the concentration of a substance in mol per dm³
1.
M = n/v ...................... Equation 1
M = molarity of methanol, n = number of mole of methanol, v = volume of the solvent/water/solution.
<em>n = g/m.m</em>
<em>Where g = mass of methanol, m.m = molar mass of methanol.</em>
<em>g = 6.4 g, m.m = 32 g /mole.</em>
<em>n = 6.4/32 = 0.2 mole</em>
<em>and ,</em>
<em>v = m/d </em>
<em>Where m = mass of water, d = density of water</em>
<em>m = mass of 50 moles of water = 18×50 = 900 g.</em>
d = 1000 g/dm³.
v = 900/1000 = 0.9 dm³
Substituting the value of v and n into equation 1
M = 0.2/0.9
M = 0.22 mol/dm³
2.
M = n/v
v = volume of the solution
v = (mass of methanol + mass of water in the solution)/density of the solution
v = [(900+6.4)/1000]/1.03
v = 0.9064/1.03
v = 0.88 dm³
n = 0.2 mole
Therefore,
M = 0.2/0.88
M = 0.23 mol/dm³
