Answer:
Pencil is always used to mark chromatography paper or TLC plates because ink may run and interfere with the chromatogram. ... As soon as the paper/plate is taken out, mark the solvent front with a pencil before the solvent evaporates and the front becomes impossible to see.
Answer:
1) 10.0 moles of NO
2) 25 moles of NaCl
3) 1200 moles of CO2
1. How many moles of nitrogen monoxide can be made using 5.0 moles of oxygen in the following composition reaction?
N2 + O2 → 2NO
For 1 mol N2 we need 1 mol O2 to produce 2 moles of NO
For 5.0 moles of N2 we need 5.0 moles of O2 to produce 10.0 moles of NO
2. The neutralization of an acid with a base is a double replacement reaction in which a salt and water are formed. If you start with 25 moles of HCl and neutralize it with NaOH how many moles of NaCl will be formed?
HCl + NaOH → NaCl + H2O
For 1 mol HCl we need 1 mol NaOH to produce 1 mol of NaCl and 1 mol H2O
For 25 moles of HCl we need 25 moles of NaOH to produce 25 moles of NaCl and 25 moles of H2O
3. A car burns gasoline (octane – C8H18) with oxygen. If you drive to Salt Lake and burn 150 moles of octane how many moles of carbon dioxide are you producing?
2C8H18 + 25O2 → 16CO2 + 18H2O
For 2 moles of octane we need 25 moles of O2 to produce 16 moles of CO2 and 18 moles of H2O
For 150 moles of octane we need 25*75 = 1875 moles of O2
To produce 16*75 = 1200 moles of CO2 and 18*75= 1350 moles
Explanation:
Answer:
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed. The distinction between physical and chemical change is not clear cut.
Explanation:
Answer:
7.5 gm left
Explanation:
Bismuth-210 has a half life of 5 days
15 days is 15/5 = 3 half lives
since half the amount is left in 5 days or 1 half life
(1/2) x (1/2) x (1/2) the staring amount would be left in
3 half lives. so 1/8 is left
(1/8) x 60.0 = 7.5 gm left
Answer:
Calcium
Explanation:
is a silver-gray metal which takes its name from the Latin word calx, which means lime. It is the fifth most abundant element in the earth's crust and is widely distributed as limestone (CaCO3), quicklime (CaO) and calcium fluoride.
