Answer:
2.2 x 10²² molecules.
Explanation:
- Firstly, we need to calculate the no. of moles in (6.0 g) sodium phosphate:
<em>no. of moles = mass/molar mass </em>= (6.0 g)/(163.94 g/mol) = <em>0.0366 mol.</em>
- <em>It is known that every mole of a molecule contains Avogadro's number (6.022 x 10²³) of molecules.</em>
<em />
<u><em>using cross multiplication:</em></u>
1.0 mole of sodium phosphate contains → 6.022 x 10²³ molecules.
0.0366 mole of sodium phosphate contains → ??? molecules.
<em>∴ The no. of molecules in 6.0 g of sodium phosphate</em> = (6.022 x 10²³ molecules)(0.0366 mole)/(1.0 mole) = <em>2.2 x 10²² molecules.</em>
(a) Iron (iii) sulphate:
From the periodic table:
mass of iron = 55.845 grams
mass of sulphur = 32.065 grams
mass of oxygen = 16 grams
Iron (iii) sulphate has the formula: Fe2(SO4)3
molar mass = 2(55.845) + 3(32.065) + 3(4)(16) = 399.885 grams
(b) Sodium hydroxide:
From the periodic table:
mass of sodium = 22.989 grams
mass of oxygen = 16 grams
mass of hydrogen = 1 gram
Sodium hydroxide has the formula: NaOH
molar mass = 22.989 + 16 + 1 = 39.989 grams
(c) Barium carbonate
From the periodic table:
mass of barium = 137.327 grams
mass of carbon = 12 grams
mass of oxygen = 16 grams
Barium carbonate has the formula: BaCO3
molar mass = 137.327 + 12 + 3(16) = 197.327 grams
(d) ammonium nitrate:
From the periodic table:
mass of nitrogen = 14 grams
mass of hydrogen = 1 gram
mass of oxygen = 16 grams
Ammonium nitrate has the formula: NH4NO3
molar mass = 14 + 4(1) + 14 + 3(16) = 80 grams
(e) Lead (iv) oxide
From the periodic table:
mass of lead = 207.2 grams
mass of oxygen = 16 grams
Lead (iv) oxide has the formula: PbO2
molar mass = 207.2 + 2(16) = 239.2 grams
From the above calculations, we can see that:
Iron (iii) sulphate has the greatest mass.
Answer:
this is what i got
Explanation:
α-decay: When a radioactive nucleus disintegrates by emitting an αα-particle, the atomic number decreases by two and mass number decreases by four. Example: 88Ra226→86Rn222+2He4.
