Answer: Lexington and Concord
Explanation: The British were trying to find weapons and could not find them.
First a balanced reaction equation must be established:

→

Now if mass of aluminum = 145 g
the moles of aluminum = (MASS) ÷ (MOLAR MASS) = 145 g ÷ 30 g/mol
= 4.83 mols
Now the mole ratio of Al : O₂ based on the equation is 4 : 3
[
4Al +
3 O₂ → 2 Al₂O₃]
∴ if moles of Al = 4.83 moles
then moles of O₂ = (4.83 mol ÷ 4) × 3
=
3.63 mol (to 2 sig. fig.)
Thus it can be concluded that
3.63 moles of oxygen is needed to react completely with 145 g of aluminum.
Answer:
0.0498 mol
Explanation:
Number of moles = concentration in mol/L × volume in L
Concentration = 1 M = 1 mol/L
Volume = 49.8 mL = 49.8/1000 = 0.0498 L
Number of moles = 1×0.0498 = 0.0498 mol
Answer:
33.33% = 33%
Explanation:
MgCO3(s) + 2HCl (aq) --> MgCl2(aq) + H20(l) + CO2(g)
1 mole of MCO3 will produce → 1 mole of CO2
We need to get the number of mole of CO2:
and when we have 0.22 g of CO2, so number of mole = mass / molar mass
Moles = 0.22 g / 44 g/mol = 0.005 mole
Moles of Mg = moles of CO2 = 0.005 mole
Mass of Mg = moles * molar mass
= 0.005 * 84 /mol = 0.42 g
Percent of MgCO3 by mass of Mg = 0.42 g / 1.26 * 100
=33.33 %
Answer:
<u>Reasons water is important </u>
Imagine earth without water. The soil, with no water in it and nothing growing on it, would be lifeless, dead, collapsed into dust, sand, clay or rock.
-Water consumption helps lubricate and cushion your joints, spinal cord, and tissues. This will help you enjoy physical activity and lessen discomfort caused by conditions like arthritis.
-Water is a main component of saliva. Saliva also includes small amounts of electrolytes, mucus, and enzymes. It’s essential for breaking down solid food and keeping your mouth healthy.