Answer:
(1) 0.0016 mol/L
Explanation:
Let the concentration of alcohol after 3.5 hours be y M
The reaction follows a first-order
Rate = ky^0 = change in concentration/time
k = 6.4×10^-5 mol/L.min
Initial concentration = 0.015 M
Concentration after 3.5 hours = y M
Time = 3.5 hours = 3.5×60 = 210 min
6.4×10^-5y^0 = 0.015-y/210
y^0 = 1
0.015-y = 6.4×10^-5 × 210
0.015-y = 0.01344
y = 0.015 - 0.01344 = 0.00156 = 0.0016 mol/L (to 4 decimal places)
Answer:
0.846 moles.
Explanation:
- This is a stichiometric problem.
- The balanced equation of complete combustion of butane is:
C₄H₁₀ + 6.5 O₂ → 4 CO₂ + 5 H₂O
- It is clear from the stichiometry of the balanced equation that complete combustion of 1.0 mole of butane needs 6.5 moles of O₂ to produce 4 moles of CO₂ and 5 moles of H₂O.
<u><em>Using cross multiplication:</em></u>
- 1.0 mole of C₄H₁₀ reacts with → 6.5 moles of O₂
- ??? moles of C₄H₁₀ are needed to react with → 5.5 moles of O₂
- The number of moles of C₄H₁₀ that are needed to react with 5.5 moles of O₂ = (1.0 x 5.5 moles of O₂) / (6.5 moles of O₂) = 0.846 moles.
Answer:
Yes
Explanation:
Standard temperature and pressure conditions are defined as 1 atm pressure and 273.15 K. On the other hand, standard ambient temperature and pressure conditions are defined as 1 atm pressure and 298.15 K.
Notice, however, that the only change between them is in temperature.
In any standard conditions, the standard atmospheric pressure is equal to 1 atm.
At sea level, the atmospheric pressure is also equal to 1 atm.
Therefore, we may conclude that the standard atmospheric pressure is equivalent to the normal air pressure at sea level. With an increase in altitude, however, the atmospheric pressure decreases.
Answer:
Mass of hydrogen produced = 2.1 g
Mass of excess reactant left = 25.2 g
Explanation:
Given data:
Mass of Mg = 50.0 g
Mass of HCl = 75.0 g
Mass of hydrogen produced = ?
Mass of excess reactant left = ?
Solution:
Chemical equation:
Mg + 2HCl → MgCl₂ + H₂
Number of moles of Mg:
Number of moles = mass/molar mass
Number of moles = 50 g/ 24 g/mol
Number of moles = 2.1 mol
Number of moles of HCl:
Number of moles = mass/molar mass
Number of moles = 75 g/ 36.5 g/mol
Number of moles = 2.1 mol
now we will compare the moles of hydrogen gas with both reactant.
Mg : H₂
1 : 1
2.1 : 2.1
HCl : H₂
2 : 1
2.1 : 1/2×2.1 = 1.05 mol
HCl is limiting reactant and will limit the yield of hydrogen gas.
Mass of hydrogen:
Mass = number of moles × molar mass
Mass= 1.05 mol ×2 g/mol
Mass = 2.1 g
Mg is present in excess.
Mass of Mg left:
HCl : Mg
2 : 1
2.1 : 1/2×2.1 = 1.05
Out of 2.1 moles of Mg 1.05 react with HCl.
Moles of Mg left = 2.1 mol - 1.05 mol = 1.05 mol
Mass of Mg left:
Mass = number of moles × molar mass
Mass = 1.05 mol × 24 g/mol
Mass = 25.2 g
It's important to understand your three states of matter because it helps you understand your surrounding and also what things change shape and why and what things stay the same and why.
