Answer:
D = Mass = 42.6 g
Explanation:
Given data:
Mass of phosphorus react = 33 g
Mass of oxygen needed = ?
Solution:
Chemical equation:
4P + 5O₂ → 2P₂O₅
Number of moles of phosphorus:
Number of moles = mass/molar mass
Number of moles = 33 g/ 30.97 g/mol
Number of moles = 1.065 mol
now we will compare the moles of phosphorus and oxygen.
P : O₂
4 : 5
1.065 : 5/4×1.065 = 1.33mol
Mass of oxygen needed:
Mass = number of moles × molar mass
Mass = 1.33 mol × 32 g/mol
Mass = 42.6 g
Thus, 43.6 g of oxygen needed to react with 33 g of phosphorus.
Answer:
$182 is the value of the gold in the coin
Explanation:
Diameter is 2r, the ratio of the coin is = 1.62cm / 2 = 0.81cm
Following the formula of the volume of the coin:
V = π r² h
V = π*(0.81cm)²*0.085cm
V = 0.172cm³ = mL
As the density of the gold is 19.32g/mL, the mass of 0.1752mL of gold is:
0.1752mL * (19.32g / mL) =
3.385g is the mass of the coin
As the price of the gold is $53.90 / g, the value of the gold in the coin is:
3.385g * ($53.90 / g) =
<h3>$182 is the value of the gold in the coin</h3>
