The purpose of a chemical equation is to relate the amounts of reactants to the amounts of products based on the rate each is consumed. In this problem, one mole of sulfuric acid is consumed along with two moles of sodium cyanide to produce two moles of hydrocyanic acid and one mole of sodium sulfate. The relationship between sodium cyanide and sodium sulfate is 2:1, meaning that two moles of NaCN is required to produce one mole of sodium sulfate.
To produce 4.2 moles of sodium sulfate, two times this amount of NaCN is required. This means that you would need 8.4 moles of sodium cyanide.
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Lifting the backpack off the floor. Force is being applied in only one direction then (up) which is what constitutes as work. Carrying the box of crayons applies force in two directions (up and forward), which cancel each other out. Work has a vector, which is a quantity containing both direction and magnitude (one, finite direction, not two).
The reaction for the combustion of methane can be expressed as follows.
CH4 + 2O2 --> CO2 + 2H2O
We solve first for the amount of carbon dioxide in moles by dividing the given volume by 22.4L which is the volume of 1 mole of gas at STP.
moles of CO2 = (5.6 L) / (22.4 L/1 mole)
moles of CO2 = 0.25 moles
Then, we can see that every mole of carbon dioxide will need 1 mole of methane
moles methane = (0.25 moles CO2) x (1 moles O2/1 mole CO2)
= 0.25 moles CH4
Then, multiply this by the molar mass of methane which is 16 g/mole. Thus, the answer is 4 grams methane.
The first part of Dalton's model is that all matter is made of atoms, and these atoms are indivisible.
The second part of this model is that atoms of an element have identical masses and identical propertes.
At last, the third part of Dalton's model is that all compounds are formed by two or more different type of atoms combined.
