Answer:
w = -531 kJ
1. Work was done by the system.
Explanation:
Step 1: Given data
- Heat gained by the system (q): 687 kJ (By convention, when the system absorbs heat, q > 0).
- Change in the internal energy of the system (ΔU°): 156 kJ
Step 2: Calculate the work done (w)
We will use the following expression.
ΔU° = q + w
w = ΔU° - q
w = 156 kJ - 687 kJ
w = -531 kJ
By convention, when w < 0, work is done by the system on the surroundings.
Answer: 
Explanation:
Heat of reaction or enthalpy change is the energy released or absorbed during the course of the reaction.
It is calculated by subtracting the enthalpy of reactants from the enthalpy of products.

= enthalpy change = ?
= enthalpy of products
= enthalpy of reactants
For the given reaction :



Answer:
26.7% is the percent composition by mass of sulfur in a compound named magnesium sulfate.
Explanation:
Molar mass of compound = 120 g/mol
Number of sulfur atom = 1
Atomic mass of sulfur = 32 g/mol
Percentage of element in compound :

Sulfur :

26.7% is the percent composition by mass of sulfur in a compound named magnesium sulfate.
Don't blame me if you get it wrong i'm a dumb but yet successful student
Warm blood gives deep-sea fish a boost, according to Wegner. The opah's muscles and nervous system likely function faster than an equivalent fish with cold blood. ... This fish, the southern opah, lives in colder waters than the northern opah, so it would be harder to keep warm, Wegner said — but even more beneficial.
Answer : Option A) Translation
Explanation : A composition of reflections over parallel lines is the same as a <u>Translation.</u>
To identify if the composition of reflections over parallel lines are same as translation or not?
We can check using a picture of some shape in the plane. Place the picture on the right side of two vertical parallel. Now, we can see the reflected the shape over the nearest parallel line, then check the reflection over the other parallel line. We see that the shape winds up in the same orientation, like it was just shifted over to the right. Hence, it is translation.