Answer:
E. Cool a solvent below room temperature
Explanation:
When a solution that has had more solute dissolved at a higher temperature is now cooled, it becomes supersaturated at the lower temperature. Because that supersaturated solution holds more solute than is stable at the lower temperature, crystals start to form.
Last option: Disproves or proves
Answer:
mass of hydrogen collected is 0.016 gram
Explanation:
Given values:
For calculating mass we have to find the number of moles first
Ideal gas equation PV =nRT
Volume= 195 ml
Pressure: 753 torr =0.99 atm
Temperature: 25+273= 298 Kelvin
Ideal gas constant R= 0.0821 Latm/molK
Number of moles n= ?
So n= PV/RT
Adding the values
n= = (753 torr)(1 atm/760 torr)(195 mL)(1 L/1000 mL)/(0.0821 L·atm/mol·K)(273 K)
n = 0.007897 moles of H₂
Now mass of hydrogen collected = number of moles x Molar mass of H₂
= 0.007897 x 2
= 0.0157 g H₂
Now mass of hydrogen collected is 0.016 gram (rounding the amount)