Answer:
Organic waste in landfills generates, methane, a potent greenhouse gas. By composting wasted food and other organics, methane emissions are significantly reduced. Compost reduces and in some cases eliminates the need for chemical fertilizers. Compost promotes higher yields of agricultural crops.
Explanation:
There are 1000 meters in 1 Kilometer.
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To take the percent by mass of this element, we use the
formula:
% mass = (mass of element / mass of ore) * 100%
% mass = (47.5 g / (660 kg * 1000 g / kg)) * 100*
<span>% mass = 7.20 x 10^-3 %</span>
Missing question:<span> How many grams of oxygen are needed for complete combustion of the toluene?
Chemical reaction: </span>C₇H₈ + 9O₂ → 7CO₂ + 4H₂<span>O.
V(</span>C₇H₈) = 8,30 ml.
d(C₇H₈) = 0,867 g/ml.
n(C₇H₈) = V(C₇H₈) · d(C₇H₈).
m(C₇H₈) = 8,3 ml · 0,867 g/ml.
m(C₇H₈) = 7,19 g.
n(C₇H₈) = m(C₇H₈) ÷ M(C₇H₈).
n(C₇H₈) = 7,19 g ÷ 92,14 g/mol = 0,078 mol.
From chemical reaction: n(C₇H₈) : n(O₂) = 1 : 9.
n(O₂) = 9 · 0,078 mol = 0,702 mol.
m(O₂) = 0,702 mol · 32 g/mol = 22,5 g.
