Chemistry - moles (1 Viewer)

[Selfstudy]

Hi
I need help with moles plzzzzzz............
It's so confusing.
Anything to make it less complicated.
Useful notes/sites

 

[eyeseeyou]

https://www.khanacademy.org/science/health-and-medicine/lab-values/v/the-mole-and-avogadro-s-number

It's confusing at first but over time, you'll be able to understand it

 

[Shuuya]

Do you have any particular questions that need answering?

 

[Selfstudy]

Thanks))
I need help with changing from atoms to mass. I have the equations but they don't make sense.
And I need help with questions ie mainly word questions
Example:
In a chemistry demonstration, a teacher react sodium carbonate with excess hydrochloric acid. Calculate the mass of sodium carbonate needed to form 4.53 grams of sodium chloride.

How would you solve that.
(((And what would've the main steps be if you had to solve other questions, cause my teacher said to convert to moles)))

 

[helloimyellow]

Im on my phone atm so can't do the question, but for molar calculations usually you do the following:

1. Write balanced equation.
2. Calculate moles of any species based on data from question (in this case the moles of NaCl using moles = mass divided by molar mass).
3. If required, determine limiting and excess reagent. Here you don't have to as hydrochloric acid is excess.
3. Use stoichiometric ratios to calculate moles of other species (in this case moles of sodium carbonate).
4. Answer the question! Here, use mass = moles x molar mass to find mass of sodium carbonate.

 

[Shuuya]

Thanks))
I need help with changing from atoms to mass. I have the equations but they don't make sense.
And I need help with questions ie mainly word questions
Example:
In a chemistry demonstration, a teacher react sodium carbonate with excess hydrochloric acid. Calculate the mass of sodium carbonate needed to form 4.53 grams of sodium chloride.

How would you solve that.
(((And what would've the main steps be if you had to solve other questions, cause my teacher said to convert to moles)))

If you want to convert from atoms to mass, you first have to first convert to the number of moles of the substance, as the mass on the periodic table is the molar mass of the substance (i.e. the mass of one mole of the substance)

e.g. Calculate the molecular mass of 1.05 x 10^22 carbon monoxide molecules.

1. Convert to moles of CO by dividing by Avagadro's number:
1.05 x 10^22/6.02 x 10^23 = 0.01744... moles
2. Multiply the number of moles by the molar mass of the substance
The molar mass of CO is 12.01 + 16.00 = 28.01g
Number of moles x molar mass = 0.1744... x 28.01
= 0.488g

Therefore, there is 0.488g (3 s.f.) of CO

 

[Selfstudy]

Thanks guys

 

[jathu123]

http://www.ausetute.com.au/molreact.html

Have a look into this website, may help you

 

[BandSixFix]

If you want to convert from atoms to mass, you first have to first convert to the number of moles of the substance, as the mass on the periodic table is the molar mass of the substance (i.e. the mass of one mole of the substance)

e.g. Calculate the molecular mass of 1.05 x 10^22 carbon monoxide molecules.

1. Convert to moles of CO by dividing by Avagadro's number:
1.05 x 10^22/6.02 x 10^23 = 0.01744... moles
2. Multiply the number of moles by the molar mass of the substance
The molar mass of CO is 12.01 + 16.00 = 28.01g
Number of moles x molar mass = 0.1744... x 28.01
= 0.488g

Therefore, there is 0.488g (3 s.f.) of CO

lol I thought that said Avocado ;-;

 

[InteGrand]

lol I thought that said Avocado ;-;

In fact, the true spelling is neither "Avocado" nor "Avagadro". It is "Avogadro".

His Wikipedia page is here: https://en.wikipedia.org/wiki/Amedeo_Avogadro .

 

[Shuuya]

In fact, the true spelling is neither "Avocado" nor "Avagadro". It is "Avogadro".

His Wikipedia page is here: https://en.wikipedia.org/wiki/Amedeo_Avogadro .

Me and my dodgy spelling :/

InteGrand always picks up my awkward mistakes haha