M CaCl₂: 40+(35,5×2) = 111 g/mol

6,02·10²³ molecules ---------- 111g
X molecules --------------------- 75,9g
X = (75,9×6,02·10²³)/111
X = 4,116·10²³ molecules of CaCl₂

:)

8 0

3 years ago

Why do we use moles when calculating empirical chemical formulas, but not the mass?

Arada [10]

Answer:

because moles is the chemical unit*Avogadro's number, meaning it's the amount of atoms in the given unit.

Explanation:

8 0

3 years ago

Read 2 more answers

When a lead acid car battery is recharged by the alternator, it acts essentially as an electrolytic cell in which solid lead(II)

katen-ka-za [31]

Answer:

3.81 g Pb

Explanation:

When a lead acid car battery is recharged, the following half-reactions take place:

Cathode: PbSO₄(s) + H⁺ (aq) + 2e⁻ → Pb(s) + HSO₄⁻(aq)

Anode: PbSO₄(s) + 2 H₂O(l) → PbO₂(s) + HSO₄⁻(aq) + 3H⁺ (aq) + 2e⁻

We can establish the following relations:

1 A = 1 c/s
1 mole of Pb(s) is deposited when 2 moles of e⁻ circulate.
The molar mass of Pb is 207.2 g/mol
1 mol of e⁻ has a charge of 96468 c (Faraday's constant)

Suppose a current of 96.0A is fed into a car battery for 37.0 seconds. The mass of lead deposited is:

$37.0s.\frac{96.0c}{s} .\frac{1mole^{-} }{96468c} .\frac{1molPb}{2mole^{-} } .\frac{207.2gPb}{1molPb} =3.81gPb$

6 0

3 years ago