[Part 2]-C4- calculations ➖➕➗✖️ Flashcards
When calculating balanced equations, from reacting masses. What are the steps to answer this question?
Hint: mole equation, divide each number of moles, decimal number
1) work out the mr
2) use the moles, mass and Mr equation to work out the number of moles. [no. of moles= mass
—————
Mr
3) then divide each number of moles, by the smallest number of moles.
4) Top tip: If a number is a decimal (instead of a whole number), multiply it by a number until you get a whole number!
What is the equation for working out the mass when I have the concentration and volume?
Hint: ÷1000
Mass= concentration x volume
—————————————-
1000
What is the unit for volume?
Hint: not cm
- the unit for volume is:
- dm^3
What is the unit for concentration?
Hint: g
g/dm^3
What is the rearranged equation to work out volume, if I have mass and concentration ?
Hint: not x 1000
Volume= mass
—————-
concentration
What is the equation for concentration, if I have mass and volume?
Hint: ×1000
Concentration= mass
————— x 1000
volume
How do I convert from g/dm^3 to dm^3 ?
Hint: think of it as ml and litres. 1L of 🥛 (milk) =1000ml of 🥛 (milk). So1g/dm^3= 1000 dm^3
Divide by 1000
What are the steps for calculating the limiting reactant?
1) work out the no. of moles by using the mass, Mr and moles equation.
2) Then put it into a ratio
3) then do the actual ratio, by satisfying the ratio
4) then determine the limiting reactant.
Fill in the gaps: when calculating balanced equations, from reacting masses, if a number is a _______ [instead of a whole number], ________ it by a number until you get a whole number!
- If a number is a decimal [instead of a whole number], multiply it by a number until you get a whole number!
What is the equation linking concentration, mass and volume in cm^3 ?
concentration= mass [g] ÷ volume of solution [cm^3] (x1000)
What is the equation linking concentration, mass and volume in dm^3 ?
- concentration [g/dm^3]= mass [g] ÷ volume of solution [dm^3]
