Evaporation technique is used to separate a compound dissolved in a solvent by vaporizing the solvent and converting it to gaseous state. This leaves behind the solid residue present in the solution after the pure solvent is vaporized. The solvent vapors can be collected and condensed to get pure solvent. But the solid residue cannot be considered pure as it is the left over solid after all the solvent is evaporated. If the solution has some impurities, the solid left over includes all of the impurities. So, we cannot obtain a pure solid in evaporation technique.
Answer:
100 j
Explanation:
bascially u j subtract 50 from 150 because the system lost 50 j but theres 150 in its surroundings
1. pesticides: that are sprayed on crops and flowers
2. global warming: warm winters have caused plants to shift their schedules. when the honey bees come out of hibernation, the flowers they need to feed on have already bloomed and died
3. pathogens carried by mites weaken bees
Answer:
(a) Moles of ammonium chloride = 0.243 moles
(b) 
(c) 60.68 mL
Explanation:
(a) Mass of ammonium chloride = 13.0 g
Molar mass of ammonium chloride = 53.491 g/mol
The formula for the calculation of moles is shown below:
Thus,
<u>Moles of ammonium chloride = 0.243 moles</u>
(b) Moles of ammonium chloride = 0.243 moles
Volume = 295 mL = 0.295 L ( 1 mL = 0.001 L)
(c) Moles of ammonium chloride = 0.0500 moles
Volume = ?
Molarity = 0.824 M
<u>Volume = 0.05 / 0.824 L = 0.06068 L = 60.68 mL</u>
HCl = H⁺ + Cl⁻
c(HCl)=9.8*10⁻⁵ mol/l
pH=-lg[H⁺]
[H⁺]=c(HCl)
pH=-lg{c(HCl)}
pH=-lg{9.8*10⁻⁵}=4.009
pH=4.009
