Answer:
C. the boiling point of water
Explanation:
B is correct because boiling point only usually differs among the same substance when pressure changes. So say you take one solution onto a mountain top and another at sea level, the boiling point will not be the same, but here we assume they are in the same place so it won't.
A cannot be because the containers are all different shapes (and we aren't talking about like molecular shape of water from what I assume, we mean macroscopically, so that can't be).
B cannot be because we have 4 different temperatures.
D cannot be because we have 4 different temperatures, and therefore different amounts of steam will be released per minute as not all the waters have reached boiling.
Answer:
85.5 mmHg is the pressure of the gas sample when the valve is opened.
Explanation:
The combined gas equation is,

where,
= initial pressure of gas in container A = 165 mmHg
= final pressure of gas = ?
= initial volume of gas in container A= 
= final volume of gas = 135 mL + 117 mL = 252 mL
= initial temperature of gas in container A = 
= final temperature of gas = 
Now put all the given values in the above equation, we get:



85.5 mmHg is the pressure of the gas sample when the valve is opened.
2Cu + S = Cu₂S
n(Cu)=m(Cu)/M(Cu)
n(Cu)=12.71/63.55=0.2 mol
n(S)=m(s)/M(S)
n(S)=8.000/32.01=0.25 mol
Cu:S 2:1
0.2 mol : 0.25 mol copper deficiency, sulphur in excess
theoretical mass of copper (I) sulfide
m(Cu₂S)=M(Cu₂S)n(Cu)/2
the percentage yield in the reaction is
w=m'(Cu₂S)/m(Cu₂S)=2m'(Cu₂S)/M(Cu₂S)n(Cu)
w=2*14.72/(159.16*0.2)=0.925 (92.5%)
Most definitely a mixture because it's usually a mix of puréed grapes,water,and sugar.
Isotopes:) hope this helps