Answer: 20.7 kJ
Explanation:
According to first law of thermodynamics:
=Change in internal energy
q = heat absorbed or released
w = work done or by the system
w = work done on the system=
{Work is done on the system is positive as the final volume is lesser than initial volume}
w = 4.51 kcal =
(1kcal = 4.184kJ)
q = +1.79 kJ {Heat absorbed by the system is positive}

Thus
for a system that receives 1.79 kJ of heat from surroundings and has 4.51 kcal of work done on it at the same time is 20.7 kJ
Abiotic things are like rocks...dirt...water vs. biotic is living things or something that was living
4 moles of sugar.
Explanation:
A mole is defined as the amount of a substance contained in Avogadro's number of particles 6.02 x 10²³.
1 mole of substance = 6.02 x 10²³. molecules
Given that;
the sample of sugar contains 1.505 x 10²³.molecules
The number of moles in this amount of sugar is 4 moles
Learn more:
Number of moles brainly.com/question/13064292
#learnwithBrainly
Sulphur Dioxide. Toxic. Don't eat it.
Answer:
You may be referring to the gas that makes up 21% of the earth's atmosphere, which is oxygen.
Explanation:
According to NASA, the gases in Earth's atmosphere include:
Nitrogen — 78 percent
Oxygen — 21 percent
Argon — 0.93 percent
Carbon dioxide — 0.04 percent
(Trace amounts of neon, helium, methane, krypton and hydrogen, as well as water vapor)