March 28, 2024, 05:13:18 AM
Forum Rules: Read This Before Posting


Topic: Product mass  (Read 2169 times)

0 Members and 1 Guest are viewing this topic.

Offline timus221

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
Product mass
« on: October 16, 2017, 09:31:50 AM »
We have 5g of SiO2 and 25g 30% solution of NaOH. Calculate a mass of product. Please help

SiO2+2NaOH =Na2SiO3+H2O

Offline Arkcon

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 7367
  • Mole Snacks: +533/-147
Re: Product mass
« Reply #1 on: October 16, 2017, 10:23:19 AM »
Greetings, timus221:, I'd like to welcome you and all the new students to the Chemical Forums.  But I'd like to ask you to trouble yourself to read our Forum Rules{click}. You already accepted them when you signed up for our forum, and they apply to you, whether you agree with them or not, or even if you're unaware of them. 

Our rules specify that we want to see your work, and then, we want to give you hints, so that you learn for yourself.  It doesn't matter if you're a new student, or a dedicated amateur, we need to know what you know, and what you think, so we know what level you're at, so we can give useful hints, so your knowledge can grow.   

Let's get started:

We have 5g of SiO2 and 25g 30% solution of NaOH. Calculate a mass of product. Please help

SiO2+2NaOH =Na2SiO3+H2O


You've been given an equation, that relates products to reactants.  You've been given mass, of reactants, and need mass of products.  But the units of your equation aren't mass.  You will have to convert back and forth.  You will also have to be sure you have enough of both reactants, you can only get as much product as you have enough reactant -- but which one do you have the least of?

There are tasks usually covered in class notes and text books, before these problems are assigned.  Why not try a few of the steps suggested, and show us what you're able to figure out?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline timus221

  • Very New Member
  • *
  • Posts: 2
  • Mole Snacks: +0/-0
Re: Product mass
« Reply #2 on: October 16, 2017, 10:35:41 AM »
Ok so in my view it will be :

firstly mass of NaOH 0,3*25g=7,5g

I have to check the insufficiency of reactant:

SiO2+2NaOH =Na2SiO3+H2O

5g-----------xg
60g/mol----80g/mol (NaOH)

x=6,67g so there is excess of NaOH , so

5g------------yg (Na2SiO3)
60g/mol-----122g/mol (Na2SiO3)

y=10,17g

Is it correct ?

Offline Borek

  • Mr. pH
  • Administrator
  • Deity Member
  • *
  • Posts: 27637
  • Mole Snacks: +1799/-410
  • Gender: Male
  • I am known to be occasionally wrong.
    • Chembuddy
Re: Product mass
« Reply #3 on: October 16, 2017, 03:12:37 PM »
5g------------yg (Na2SiO3)
60g/mol-----122g/mol (Na2SiO3)

y=10,17g

Is it correct ?

Looks OK.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Sponsored Links