<h3><u>Answer;</u></h3>
= 1.615 moles
<h3><u>Explanation</u>;</h3>
The molar mass of NO2
= 46.01 g/mol
The mass of NO2 given is 74.3 g
Number moles = mass/ molar mass
= 74.3 g/ 46.01 g/mol
= 1.615 moles
Hi!
Answer:
The change in temperature.
Explanation:
Snow forms at 0 °C, when water vapor converts directly into solid ice crystals. Sleet forms when raindrops fall through a layer of air colder than 0 °C. This means that from the time it was snowing to the time it started sleeting the air has gotten warmer but one layer of air stayed cold, hence the formation of sleet. Freezing rain is rain that freezes when it hits a cold surface. This means that from the time it was sleeting to the time there was freezing rain the air had completely warmed and is now above 0 °C but the ground and all other surfaces are still cold.
I hope this helps, as this happens all the time where I live! :)
Answer:
CH₂ ; 67.1 %
Explanation:
To determine the empirical formula we need to find what the mole ratio is in whole numbers of the atoms in the compound. To do that we will first need the atomic weights of C and H and then perform our calculation
Assume 100 grams of the compound.
# mol C = 85.7 g / 12.01 g/mol = 7.14 mol
# mol H = 14.3 g / 1.008 g/mol = 14.19 mol
The proportion is 14.9 mol H/ 7.14 mol C = 2 mol H/ 1 mol C
So the empirical formula is CH₂
For the second part we will need to first calculate the theoretical yield for the 12.03 g NaBH₄ reacted and then calculate the percent yield given the 0.295 g B₂H₆ produced.
We need to calculate the moles of NaBH₄ ( M.W = 37.83 g/mol )
1.203 g NaBH₄ / 37.83 g/mol = 0.0318 mol
Theoretical yield from balanced chemical equation:
0.0318 mol NaBH₄ x 1 mol B₂H₆ / mol NaBH₄ = 0.0159 mol B₂H₆
Theoretical mass yield B₂H₆ = 0.0159 mol x 27.66 g/ mol = 0.440 g
% yield = 0.295 g/ 0.440 g x 100 = 67.1 %
The molarity of NaOH needed is calculated as follows
calculate the moles of KhC8h4O4
that is moles = mass/molar mass of KhC8h4O4(204.22 g/mol)
=0.5632g /204.22g/mol= 2.76 x10^-3 moles
write the equation for reaction
khc8h4O4 + NaOH ---> KNaC8h4O4 + H2O
from the equation above the reacting ratio of KhC8h4O4 to NaOh is 1:1 therefore the moles of Naoh is also 2.76 x10^-3 moles
molarity of NaOh = (moles of NaOh / volume ) x 1000
that is { (2.76 x10^-3) / 23.64} x100 =0.117 M