Answer:
70.6 %
Explanation:
First step, we define the reaction:
2P + 3Br₂ → 2PBr₃
We determine the moles of reactant:
35 g . 1mol / 159.8 g = 0.219 moles
We assume, the P is in excess, so the bromine is the limiting reagent.
3 moles of Br₂ can produce 2 moles of phophorous tribromide
Then, 0.219 moles may produce (0.219 . 2) /3 = 0.146 moles of PBr₃
We convert moles to mass:
0.146 mol . 270.67 g /mol = 39.5 g
That's the 100 % yield reaction, also called theoretical yield. The way to determine the % yield is:
(Yield produced / Thoeretical yield) . 100
(27.9 / 39.5) . 100 = 70.6 %
They use fans and air conditioning in the summer because its hot, which means they use energy and in the winter, there is no need because its cold so less energy.
Answer:
The Photosynthesis process
Explanation:
Plants, algae, and some other organisms can transform the sunlight energy into chemical energy. The photosynthesis process occur thanks to the chloroplasts. The chloroplast is an organelle found in all green plants. Inside of the chloroplast you can find the thylakoids which are arranged in stacks named grana, they have membranes with chloropyll a photosynthetic pigment, also you can find the photosystems, they are functional and structural units of protein complexes. The thylakoids capture the light and allow the reactions to transform CO2. The set of reactions that occurs in the chloroplasts are known as the Calvin cycle.
The general equation of photosynthesis is:

6 CO2 + 6 H2O + Energy -> C6H12O6 + 6 O2
Carbon Dioxide + water + Light -> Glucose (sugar) + Oxygen
After, this glucose is transformed into pyruvate, and it allowed the release of denosine triphosphate (ATP) by cellular respiration. The ATP is an organic chemical that is requires for the cell to perform any process (any kind or work).