Answer:
The first one
Explanation:
Elements are as simple as it gets
Letter d, because they are both alkali metals (group one)
Answer: C excess reactant
Reason: It is not catalyst because catalyst are not consumed. It is not product because it was one of the reactants. It is not limiting because there was excess left over.
Answer: Chloroplasts
Reasoning: I just had my 830th lesson in school about these
Answer:
3.56x10^24 molecules
Explanation:
The following data were obtained from the question:
Mass of Na2SO4 = 840g
Molar Mass of Na2SO4 = (23 x2) + 32 + (16x4) =46 + 12 + 64 = 142g/mol
From Avogadro's hypothesis, 1mole of any substance contains 6.02x10^23 molecules. This also gives that 1mole of Na2SO4 contains 6.02x10^23 molecules.
If 1 mole (i.e 142g) contains 6.02x10^23 molecules,
Therefore, 840g of Na2SO4 will contain = (840 x 6.02x10^23)/142 = 3.56x10^24 molecules
