Respuesta :
1) The answer is: 243.27 grams of hydrochloric acid will react completely.
Balanced chemical reaction: Au + 2HCl → AuCl₂ + H₂.
V(Au) = 3.2 cm · 3.8 cm · 2.8 cm.
V(Au) = 34.05 cm³; volume of gold.
d(Au) = 19.3 g/cm³; density of gold.
m(Au) = V(Au) · d(Au).
m(Au) = 34.05 cm³ · 19.3 g/cm³.
m(Au) = 657.13 g; mass of gold.
n(Au) = m(Au) ÷ M(Au).
n(Au) = 657.13 g ÷ 196.97 g/mol.
n(Au) = 3.33 mol; amount of gold.
2) From balanced chemical reaction: n(Au) : n(HCl) = 1 : 2.
n(HCl) = 2 · n(Au).
n(HCl) = 2 · 3.33 mol.
n(HCl) = 6.66 mol; amount of hydrochloric acid.
M(HCl) = 36.46 g/mol; molar mass of hydrochloric acid.
m(HCl) = n(HCl) · M(HCl).
m(HCl) = 6.66 mol · 36.46 g/mol.
m(HCl) = 243.27 g; mass of hydrochloric acid.
Answer:
243.50 grams of hydrochloric acid will react completely with a block of gold.
Explanation:
Mass of gold = m
Length of gold block = l = 3.2 cm
Breadth of gold block = b = 3.8 cm
height of gold block = h = 2.8 cm
Volume of the gold = V = l × b × h = 3.2 cm × 3.8 × cm × 2.8 cm
V = [tex]34.048 cm^3=34.048 mL[/tex] ([tex]1 cm^3=1 mL[/tex])
Density of gold = d = 19.3 g/ml
[tex]m=d\times V=19.3 g/ml\times 34.048 mL=657.1264 g[/tex]
Moles of gold = [tex]\frac{657.1264 g}{197 g/mol}=3.3357 mol[/tex]
[tex]Au+2HCl\rightarrow AuCl_2+H_2[/tex]
According to recation, 1 mole gold reacts with 2 moles of HCl .Then 3.3357 moles of gold will ":
[tex]\frac{2}{1}\times 3.3357 mol=6.6713 mol[/tex] of HCl
Mass of 6.6713 moles of HCl =
[tex]6.6713 mol\times 36.5 g/mol=243.50 g[/tex]
243.50 grams of hydrochloric acid will react completely with a block of gold.
