Answer:
Answer : (1) :-
Volume of water filled in the pycnometer is given as = 9.9872 mL.
Mass of pycnometer when filled with water = 23.1148 g.
Mass of empty pycnometer = 13.1455 g.
So, mass of water = (23.1148 - 13.1455) g. = 9.9693 g.
We know that,
<em> Density = Mass / Volume = (9.9693 g.) / (9.9872 mL) = </em>0.998 g/mL.
<u>It is observed that the density of water is evaluated to be 0.998 g/mL. We know that, at 4℃ the density of water becomes maximum i.e. 1 g/mL. On the other hand the temperature at which the density of water is 0.998 g/mL is 0℃. Therefore, it can be concluded that the experiment was performed at a temperature of 0℃.</u>
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Answer:
B. CaCl₂ + H₂CO₃ → CaCO₃ + 2HC
Explanation:
A balanced reaction has the same number of atoms in the both sides of the reaction. In the options:
A. CaCl₂ + H₂CO₃ → 2CaCO₃ + HCI
In this reaction there is 1 Ca in reactants and 2 in products -<em>The reaction is unbalanced-</em>
<em />
<h3>B. CaCl₂ + H₂CO₃ → CaCO₃ + 2HCl
</h3>
There is 1 Ca is both sides, 2Cl, 2H, 1C and 3 Oxygens -<em>The reaction is balanced</em>
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C. CaCl₂ + 2H₂CO₃ → CaCO₃ + HCI
There is 1 Ca in both sides but 2Cl in reactants and 1 in Cl -<em>The reaction is unbalanced-</em>
<em />
D. 2CaCl₂ + H₂CO₃ →CaCO₃ + HCI
There are 2 Ca in reactants and 1 in Ca -<em>The reaction is unbalanced-</em>
D The Part That Stays The Same
Answer:
there are approximately n ≈ 10²² moles
Explanation:
Since the radius of the earth is approximately R=6378 km= 6.378*10⁶ m , then the surface S of the earth would be
S= 4*π*R²
since the water covers 75% of the Earth's surface , the surface covered by water Sw is
Sw=0.75*S
the volume for a surface Sw and a depth D= 3 km = 3000 m ( approximating the volume through a rectangular shape) is
V=Sw*D
the mass of water under a volume V , assuming a density ρ= 1000 kg/m³ is
m=ρ*V
the number of moles n of water ( molecular weight M= 18 g/mole = 1.8*10⁻² kg/mole ) for a mass m is
n = m/M
then
n = m/M = ρ*V/M = ρ*Sw*D/M = 0.75*ρ*S*D/M = 3/4*ρ*4*π*R² *D/M = 3*π*ρ*R² *D/M
n=3*π*ρ*R² *D/M
replacing values
n=3*π*ρ*R² *D/M = 3*π*1000 kg/m³*(6.378*10⁶ m)² *3000 m /(1.8*10⁻² kg/mole) = 3*π*6.378*3/1.8 * 10²⁰ = 100.18 * 10²⁰ ≈ 10²² moles
n ≈ 10²² moles
Answer:
The answer is D part of your lab notebook used for writing vocabulary
Hope it helps!
