Quantitative Chemistry Flashcards
What is meant by the conservation of mass?
No atoms are LOST or MADE during a chemical reaction so the mass of the PRODUCTS EQUALS the mass of the REACTANTS.
What charge do metal ions have?
Positive.
What charge do most non-metal ions have?
Negative.
What charge would a group 2 ion have?
2+
What charge would a group 6 ion have?
2-
What does the overall charge of an ionic compound have to equal?
0
What would be the formula for Sodium oxide?
….+…..2-
Na…O
Na.O.
….2…
What would be the formula for calcium hydroxide?
…..2+…….-
Ca…..OH
Ca(OH)….
…………2..
What is relative atomic mass (Ar)?
It is the AVERAGE MASS of the ISOTOPE of that element weighed to take into account of the ABUNDANCE of each ISOTOPE.
How do you work out moles of an element/compound?
mass (g) / relative atomic mass Ar or relative formula mass Mr
Calculate the number of moles of atoms in one mole of methane.
CH……
……4…
1 mole of methane molecules contains 5 moles of atoms.
What is 1 mole (Avogadro’s constant)?
602000000000000000000000 atoms
…………….23…………………………………….
6.02 x 10………………………………………..
Calculate the number of atoms in 28g of lithium. Ar Li = 7
Number of moles = 28 / 7 = 4………..
……………………………………………………23.
Number of atoms = 4 x 6.02 x 10…..
………………………………………………..24…..
Number of atoms = 2.408 x 10………
Explain the steps involved in finding the reacting mass.
1) Work out the number of MOLES of substance specified.
2) Show the RATIO to find moles of the ‘UNKNOWN’
3) Calculate the mass (moles x relative atomic mass)
What equation do you use to calculate concentration?
………………………………3………………………………………3
concentration (g/dm) = mass (g) / volume (dm)
