stoichiometry
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how do these Qs thanks
1.a sample of hydrated zso4.nh2o is formed by o.1 mol zso4 combinining with 7.2g of water what is the value of n
2.in an experiment 3.0 mol of sodium hydrogencarbonate is heated according to the following chemical equation
2nahco3 ---> na2co3+h20+co2
what is the volume of carbon dioxide measured at room temperature and pressure produced in this experiment
3.the reaction between hydrogen gas and oxygen gas is shown below
2h2+ 02 -----> 2h20
which of the following statment is correcta 8g of steam cab be produced from 8 g of oxygen gas (which i think is confirm wrong)
b 4 g of hydrogen reacting with 2g of oxygen produced 4g of hydrogen
c 0.5mol of steam can be produced from 0.25 mol of oxygen gas
d 1.0g of steam cab be produced from 1.0g of hydrogen gas
4. write an ionic equation for
agno3(aq) + nacl(aq) -----> agcl(s) + nano3(aq)
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Originally posted by Ah sian:
how do these Qs thanks
1.a sample of hydrated zso4.nh2o is formed by o.1 mol zso4 combinining with 7.2g of water what is the value of n
No. of moles of water = 7.2 / (2+16) = 0.4 mol
hence 1 mol Zs04: 4 mol H2O
n = 4
2.in an experiment 3.0 mol of sodium hydrogencarbonate is heated according to the following chemical equation
2nahco3 ---> na2co3+h20+co2
what is the volume of carbon dioxide measured at room temperature and pressure produced in this experiment
According to the equation. no. of moles of NaHCO3 : CO2 = 2:1
Hence 3 mol of NaHCO3 will produce 1.5 moles of CO2.
1 mole of any gas at r.t.p = 24dm3
Hence 1.5x24 = 36 dm3 of carbon dioxide produced.
3.the reaction between hydrogen gas and oxygen gas is shown below
2h2+ 02 -----> 2h20
which of the following statment is correcta 8g of steam cab be produced from 8 g of oxygen gas (which i think is confirm wrong)
yes it's wrong definitely. mass cannot be compare directly.b 4 g of hydrogen reacting with 2g of oxygen produced 4g of hydrogen
4g H2 = 2 mol
2g O2 = 2/32 = 0.0625 mol
c 0.5mol of steam can be produced from 0.25 mol of oxygen gas
0.25 mol of O2 assuming it is limiting reactant will produce 0.5 (2 x 0.25) mol of steam.
d 1.0g of steam cab be produced from 1.0g of hydrogen gas
once again, mass cannot be compare directly.
ans is C by the way
4. write an ionic equation for
agno3(aq) + nacl(aq) -----> agcl(s) + nano3(aq)
AG+ (aq) + Cl- (aq) ==> AgCl(s)
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thanks up for more Qs to be answered
eagle u can add these Qs to ur web
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answered all liao
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thank you very much
my internet connection must have lag nv see all being answer just now
for q4 how u know which is to be cancelled
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Originally posted by Ah sian:
thank you very much
my internet connection must have lag nv see all being answer just now
for q4 how u know which is to be cancelled
Steps to write ionic equation
1 write the chemical equations
2 write the state symbols for all substances
3 cancel the spectator ions - spectator ions are ions that are present on both side of the equation. ions can only be in aqueous states.
4 write the ionic equation (those spectator ions leave out
so for the q4, since both sides have Na+ ions and Cl- ions in aqueous states. you can "cancel" it
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thanks then
i remember that once my teacher taught that something like vol or what can be compared directly
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only for gases, volume can be compared directly. this is due to the Avogadro's law which states that under conditions of constant temperature and pressure, equal volumes of different gases contain the same no. of molecules
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thanks
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wa lau can you pls add caps like NaHCO3
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3.the reaction between hydrogen gas and oxygen gas is shown below
2h2+ 02 -----> 2h20
which of the following statment is correcta 8g of steam cab be produced from 8 g of oxygen gas (which i think is confirm wrong)
yes it's wrong definitely. mass cannot be compare directly.
Do remember: Mass of reactants = Mass of products. I always believed this to be a firm concept in Chemistry, which is why you balance chemical equations in the first place.
Btw, I don't think eagle is in charge of Chemistry in ExamWorld (you can guess why, but no prizes for correct answers. Penalties for wrong answers from eagle.) Which is why I am always "criticising" (kind of why I DARE to) the Chemistry questions posted on ExamWorld. You can't doubt eagle's academic standard.
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sorry i dont know as i hardly come here
another Q
in chemical reaction how do you know that at what time has X reacted haflway
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Originally posted by Garrick_3658:
Do remember: Mass of reactants = Mass of products. I always believed this to be a firm concept in Chemistry, which is why you balance chemical equations in the first place.
Btw, I don't think eagle is in charge of Chemistry in ExamWorld (you can guess why, but no prizes for correct answers. Penalties for wrong answers from eagle.) Which is why I am always "criticising" (kind of why I DARE to) the Chemistry questions posted on ExamWorld. You can't doubt eagle's academic standard.
and also what you mean by Mass of reactants = Mass of products.
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Originally posted by Garrick_3658:
Do remember: Mass of reactants = Mass of products. I always believed this to be a firm concept in Chemistry, which is why you balance chemical equations in the first place.
Btw, I don't think eagle is in charge of Chemistry in ExamWorld (you can guess why, but no prizes for correct answers. Penalties for wrong answers from eagle.) Which is why I am always "criticising" (kind of why I DARE to) the Chemistry questions posted on ExamWorld. You can't doubt eagle's academic standard.
That's why must try to persuade UltimaOnline to help out at ExamWorld
