According to the periodic table, carbon's molar mass is 12.011 grams per mole (that's the small number under the element). So, just multiply like this to get the answer:

So, there are approximately 0.208 grams in 2.5 moles of carbon.
Answer:
The answers are options b , c and d.
Hope this helps.
Answer: nn
Explanation:
The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer (US spelling) is a unit of length in the metric system, equal to one billionth (short scale) of a metre (0.000000001 m).
Answer:
The combustion of 59.7 grams of methane releases 3320.81 kilojoules of energy
Explanation:
Given;
CH₄ + 2O₂ → CO₂ + 2H₂O, ΔH = -890 kJ/mol
From the combustion reaction above, it can be observed that;
1 mole of methane (CH₄) released 890 kilojoules of energy.
Now, we convert 59.7 grams of methane to moles
CH₄ = 12 + (1x4) = 16 g/mol
59.7 g of CH₄ 
1 mole of methane (CH₄) released 890 kilojoules of energy
3.73125 moles of methane (CH₄) will release ?
= 3.73125 moles x -890 kJ/mol
= -3320.81 kJ
Therefore, the combustion of 59.7 grams of methane releases 3320.81 kilojoules of energy