What mass of natural gas (ch4) must you burn to emit 268 kj of heat? ch4(g)+2o2(g)→co2(g)+2h2o(g)δh∘rxn= −802.3kj express the mass in grams to three significant figures?

From the balanced equation, we can see that 1 mole of CH4 releases 802.3 kJ of heat upon combustion. The mass of 1 mole of CH4 is:

mass CH4 = 16.04 grams

So by ratio and proportion:

mass required = (-268 kJ) / (-802.3 kJ / 16.04 grams)

mass required = 0.334 grams

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.