The early atmosphere was probably mostly carbon dioxide, with little or no oxygen. <span>The proportion of oxygen went up because of </span>photosynthesis. The photosynthesis was conducted from <span>tiny organisms.
</span><span>cyanobacteria, or blue-green algae. </span><span>
They </span>used sunshine, water and carbon dioxide to produce carbohydrates and, yes, oxygen. This change to the atmosphere was very important because the <span>breathable air we enjoy today was created.</span>
Answer:
1. 25 moles water.
2. 41.2 grams of sodium hydroxide.
3. 0.25 grams of sugar.
4. 340.6 grams of ammonia.
5. 4.5x10²³ molecules of sulfur dioxide.
Explanation:
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In this case, since the mole-mass-particles relationships are studied by considering the Avogadro's number for the formula units and the molar mass for the mass of one mole of substance, we proceed as shown below:
1. Here, we use the Avogadro's number to obtain the moles in the given molecules of water:

2. Here, since the molar mass of NaOH is 40.00 g/mol, we obtain:

3. Here, since the molar mass of C6H12O6 is 180.15 g/mol:

4. Here, since the molar mass of ammonia is 17.03 g/mol:

5. Here, since the molar mass of SO2 is 64.06 g/mol:

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Answer:
Molality of the solution = 0.7294 M
Explanation:
Given:
Number of magnesium arsenate = 1.24 moles
Mass of solution = 1.74 kg
Find:
Molality of the solution
Computation:
Molality of the solution = Mole of solute / Mass of solution = 1.74 kg
Molality of the solution = 1.24 / 1.7
Molality of the solution = 0.7294 M
Answer:
162 g Fe₂O₃
Explanation:
To find the mass of Fe₂O₃, you need to (1) convert grams C to moles C (via molar mass from periodic table), then (2) convert moles C to moles Fe₂O₃ (via mole-to-mole ratio from reaction coefficients), and then (3) convert moles Fe₂O₃ to grams (via molar mass). It is important to arrange the ratios/conversions in a way that allows for the cancellation of units. The final answer should have 3 sig figs to reflect the given value.
Molar Mass (C): 12.011 g/mol
2 Fe₂O₃(s) + 3 C(s) ---> 4 Fe(s) + 3 CO₂(g)
Molar Mass (Fe₂O₃): 2(55.845 g/mol) + 3(15.998 g/mol)
Molar Mass (Fe₂O₃): 159.684 g/mol
18.3 g C 1 mole 2 moles Fe₂O₃ 159.684 g
-------------- x ---------------- x ------------------------- x ----------------- = 162 g Fe₂O₃
12.011 g 3 moles C 1 mole