A: The atoms in the sand were moving more quickly
Answer: 0.34 mol
Justification:
1) Hepta means 7, so heptahyrate means 7 parts of water. On mole of magnesium sulfate heptadydrate has seven moles of water.
2) The formula of magnesium sulfate heptahydrate is:
Mg SO4 . 7 H2O
3) Calcualte the number of moles of the compound by dividing the mass in grams by the molar mass of formula.
molar mass:
Mg: 24.3 g/mol
S: 32.1 g/mol
O4: 4 * 16.0 g/mol = 64.0 g/mol
H2: 2 * 1.0 g/mol = 2.0 g/mol
O: 16 g/mol
Molar mass = 24.3 g/mol + 32.1 g/mol + 64.0 g/mol + 2.0 g/mol + 16.0 g/mol = 138.4 g/mol
number of moles = mass in grams / molar mass = 6.81 g / 138.4 g/mol = 0.049 mol
4) As stated, there are 7 moles of H2O per each mol of heptahydrate compoind, so the number of moles of water is 7 * 0.049 mol = 0.343 mol
Answer: 0.34 mol
Since the temperature
is a constant, we can use Boyle's law to solve this.<span>
<span>Boyle' law says "at a constant temperature, the
pressure of a fixed amount of an ideal gas is inversely proportional to its
volume.
P α 1/V
</span>⇒
PV = k (constant)<span>
Where, P is the pressure of the gas and V is the
volume.
<span>Here, we assume that the </span>gas in the balloon is an ideal gas.
We can use Boyle's law for these two situations as,
P</span>₁V₁ = P₂V₂<span>
P₁ = 100.0 kPa = 1 x 10⁵ Pa
V₁ =
3.3 L
P₂ =
90.0 x 10³ Pa
V₂ =?
By substitution,
1 x 10⁵ Pa x 3.3 L = 90 x 10³ Pa x V₂</span><span>
V</span>₂ = 3.7 L<span>
</span><span>Hence, the volume of gas when pressure is 90.0 kPa
is 3.7 L.</span></span>
Answer:
Carbon is found in the hydrosphere dissolved in ocean water and lakes. Carbon is used by many organisms to produce shells. Marine plants use cabon for photosynthesis. The organic matter that is produced becomes food in the aquatic ecosystem.
