Answer: Option (E) is the correct answer.
Explanation:
A spontaneous reaction is defined as the process which tends to occur on its own. And, a non-spontaneous reaction is defined as a process for the completion of which we have to provide certain conditions.
For example, ice melting at 
is spontaneous primarily due to the increase in molecular disorder (dispersal of matter). Also, melting of ice is taking place on its own without any external force.
It is not necessary that all exothermic reactions will be exothermic in nature.
Thus, we can conclude that the statement all exothermic reactions are spontaneous, is false.
Answer:
She can add 380 g of salt to 1 L of hot water (75 °C) and stir until all the salt dissolves. Then, she can carefully cool the solution to room temperature.
Explanation:
A supersaturated solution contains more salt than it can normally hold at a given temperature.
A saturated solution at 25 °C contains 360 g of salt per litre, and water at 70 °C can hold more salt.
Yasmin can dissolve 380 g of salt in 1 L of water at 70 °C. Then she can carefully cool the solution to 25 °C, and she will have a supersaturated solution.
B and D are wrong. The most salt that will dissolve at 25 °C is 360 g. She will have a saturated solution.
C is wrong. Only 356 g of salt will dissolve at 5 °C, so that's what Yasmin will have in her solution at 25 °C. She will have a dilute solution.
I think the answer is a and c
I
Answer:
The new pressure of the pump is 26.05 atm or 2639.4 kPa
Explanation:
Step 1: Data given
Volume of the bicycle tire pump = 252 mL = 0.252 L
Pressure of air = 995 kPa = 9.81989 atm
The volume of the pump is reduced to 95.0 mL = 0.095 L
Step 2: Calculate the new pressure
V1*P1 = V2*P2
⇒with V1 = the initial volume of the bicycle tire pump = 0.252 L
⇒with P1 = the initial pressure of the pump = 9.81989 atm = 995 kPa
⇒with V2 = the reduced volume of the pump = 0.095 L
⇒with P2 = the new pressure = TO BE DETERMINED
0.252 L * 9.81989 atm = 0.095 L * P2
P2 = 26.05 atm
The new pressure is 26.05 atm
OR
0.252 L * 995 = 0.095 L * P2
P2 = 2639.4 kPa
The new pressure of the pump is 26.05 atm or 2639.4 kPa
The reaction is
FeO + Fe3O4 + 1/2 O2---> 2Fe2O3
Thus as shown in the balanced equation two moles of Fe2O3 are formed when 0.5 moles of O2 reacted with mixture of FeO and Fe3O4
moles of Fe2O3 = MAss / Molar mass = 4.141 / 159.69 = 0.0259 moles
So moles of O2 needed = 0.5 X 0.0259 = 0.01295
Mass of O2 = moles X molar mass = 0.01295 X 32 = 0.4144 grams
