Answer:
Choice A: Approximately joules.
Explanation:
Apply the famous mass-energy equivalence equation to find the energy that correspond to the kilograms of mass.
,
where
- stands for energy,
- stands for mass, and
- is the speed of light in vacuum.
The speed of light in vacuum is a constant. However, finding the right units for this value can simplify the calculations a lot. What should be the unit of ?
The mass given is in the appropriate SI unit:
Mass is in kilograms.
Thus, proceed with the speed of light in SI units. The SI unit for speed is meters per second. For the speed of light, .
Apply the mass-energy equivalence:
.
The unit of energy is not in joules. Don't be alerted. Consider the definition of a joule of energy. One joule is the work done on an object when a force of one newton acts on the object in the direction of the force through the distance of one meter. (English Wikipedia.)
.
However, a force of one newton is defined as the force required to accelerated an object with a mass of one kilogram (not gram) at a rate of one meter per second squared. (English Wikipedia.)
.
In other words, the mass defect here is also .
Repeat trials multiple times
No hay suficiente informacion.
Answer:
437.5 kg of first solution and 812.5 kg of second solution should be mixed to get desired solution.
Explanation:
Let the mass of the first solution be x and second solution be y.
Amount solution required = 1250 kg
x + y = 1250 kg....[1]
Percentage of ethanol in required solution = 12% of 1250 kg
Percentage of ethanol in solution-1 = 5% of x
Percentage of ethanol in required solution = 25% of y
5% of x + 25% of y =12% of 1250 kg
x + 5y = 3000 kg...[2]
Solving [1] and [2] we :
x = 437.5 kg , y = 812.5 kg
437.5 kg of first solution and 812.5 kg of second solution should be mixed to get desired solution.