The answer is Air and Gravity
B c and d are not pure substances.
The Density Calculator uses the formula p=m/V, or density (p) is equal to mass (m) divided by volume (V). The calculator can use any two of the values to calculate the third. Density is defined as mass per unit volume.
I think it is "Known".
Radioactive decay is measured using a formula where the half-life <span>of an isotope is the time it takes for the original nuclei to decay half of its original amount.</span>
CO+2 H2=CH3OH
2.85 mol Co x (2mol H2/1 mol Co)=5.70 mol just concert to grams
5.70 mol H2 x (2 g H2/1 mol H2) =11.40 grams of H2