equations//reactions Flashcards
Metal + acid –>
Metal salt + H^2
Metal + water –>
Metal hydroxide + H^2
Metal carbonate + acid –>
Metal salt + carbon dioxide + water
How many moles are there in 12g of carbon-12?
n = m / Mr
= 12g / 12g/mol
= 1 mole
How many atoms are there in 2 moles of carbon-12?
No. of atoms = N~A * n
= (6.02 10^23) 2
= 1.204 * 10^24 atoms
If 2H~2 and CO~2 are products and hydrogen is useful, what is the atom economy?
“Mr of all = 48
Mr of 2H~2 = 4
Atom economy = (4 * 100%) / 48 = 8.33%
Atom economy is 8.33%”
The mass of CuSO~4.xH~2O = 6.8g and the mass of anhydrous CuSO~4 = 4.35g. Find x
xH~2O = 6.8g - 4.35g = 2.45g
N = m / Mr is used for the CuSO~4 and the H~2O
Water = 0.1361 mol
Anhydrous salt = 0.027 mol
Ratio of anhydrous salt to water = 1:5
CuSO~4 + 5H~2O
x = 5
What volume is taken up by 10 mol of CO~2?
“N = V / 24
V = 24N
V = 24 dm^3 mol^-1 * 10mol
V = 240 dm^3”
Find the volume of 64g of O~2 gas
“2 formulas are needed here
N = m / Mr = 64g / 32
2 moles of oxygen gas
V = 24N
V = 24 * 2
V = 48dm^3”
“SiCl~4 + 2H~2O
There is 5g of SiCl~4.
Find the mass of the 2H~2O”
“The ratio of moles from SiCl~4 to 2H~2O is clearly 1:2 due to the amount of molecules
N = m / Mr = 5g / 170.1 = 0.0294
Number of SiCl~4 moles = 0.0294 mol
Using the ratio, 2H~2O has 2 times more moles than SiCl~4
0.0294 * 2 = 0.0588
There are 0.0588 mol of water”
What temperature gives a molar volume of 24dm^3 mol^-1?
“P = 101kPa (as usual) = 101000Pa
V = 24dm^3 = 0.024m^3
n = 1 mol
R = 8.314
PV = nRT
T = PV / nR
T = (101000 0.024) / (1 8.314)
T = 291.6K”
Find the concentration of 0.0032 mol of HCl dissolved in 250cm^3
“n = 0.0032 mol
V = 250cm^3 = 0.25dm^3
n = c * V
c = n / V
c = 0.0032 / 0.25
c = 0.128 mol dm^-3”
“Find the mass of KOH needed to prepare 250cm^3 of a 0.2mol dm^-3 solution
The Mr of KOH = 56.1”
“V = 0.25dm^3
c = 0.2 mol dm^-3
n = c * V
n = 0.25 * 0.2
n = 0.05mol
m = n * Mr
m = 0.05 * 56.1
m = 2.805g”
“2NaOH + H~2 SO~4
Acid volume = 0.02365dm^3
Alkali volume = 0.025dm^3
Alkali concentration = 1.25 mol dm^-3
Calculate the concentration of the acid”
“n of alkali = c V = 0.025 1.25
= 0.03125 mol
2 alkali molecules and 1 acid molecule
Ratio = 2:1
n of acid = n of alkali / 2 = 0.03125 / 2
= 0.015625 mol
So c of acid = n / V = 0.015625 mol / 0.02365 dm^3
= 0.6607 mol dm^-3
Concentration of acid is 0.6607 mol dm^-3”
“A solution contains 0.564g of CaCl~2 in 250 cm^3 of water
Find the mass concentration
“
“Mass concentration = 0.564g / 0.25dm^3
= 2.26 g dm^-3”
“A solution of NaOH has a concentration of 0.25 mol dm^-3
Calculate the mass concentration”
“Mass concentration = 0.25 * 38
= 9.5 g dm^-3”
How do the 4 main acids dissociate?
“H~2 SO~4 –> 2H+ + SO~4 2-
HCl –> H+ + Cl-
HNO~3 –> H+ + NO~3-
CH~3 COOH –> H+ + CH~3 COO-“
How many chlorine ions surround each sodium ion and how many sodiums surround each chlorine in sodium chloride?
“6 sodium around each chlorine
6 chlorine around each sodium”
How would you draw water in 3D?
“It has 2 bonded pairs and 2 lone pairs
So it is non-linear
Draw with an O in the middle
Show 2 hydrogens with a 104.5 bond angle
Also draw the 2 lone pairs”
What is the polarity of a C-H bond? You need to remember this
“Non-polar
Unusual as it seems”
What is the IMF for HCl?
“Permanent dipole-dipole forces
You have to remember this”
“Describe and explain how electrical conductivity in mercury bromide and in mercury in both solid and molten states
5 marks”
“HgBr~2 conducts when molten but not when solid
Because ions are free to move in molten state
But ions are in a FIXED LATTICE in solid state
Mercury conducts in both states
Because delocalised electrons carry charge in both states”
“There are 3 carbons in the chain
There is a chlorine on the first and second carbon
Name this organic”
“The base alkane is propane
So it is called:
1, 2 - dichloropropane”
“The base alkane is ethanol
If there are 3 bromines on one of the carbons
What is the name of this organic?”
1, 1, 1 - tribromoethane