Answer:
5 g of heptane were burned.
Explanation:
Given data:
Mass of CO₂ produced = 15.5 g
Mass of heptane burned = ?
Solution:
Balance chemical equation:
C₇H₁₆ + 11O₂ →7CO₂ + 8H₂O
First of all we will calculate the moles of CO₂ produced.
Number of moles = mass / molar mass
Molar of CO₂ = 44 g/mol
Number of moles = 15.5 g / 44 g/mol
Number of moles = 0.3523 mol
Now we will compare the moles of CO₂ and C₇H₁₆ from balance chemical equation
CO₂ : C₇H₁₆
7 : 1
0.3523 : 1/7 × 0.3523 = 0.05 mol
Mass of C₇H₁₆:
Number of moles = mass / molar mass
Mass = number of moles × molar mass
Mass = 0.05 mol / 100 g/mol
Mass = 5 g
<span>Answer: 5.32 x 10⁻³ M
Explanation:
1) The rate law for a first order reaction is:
</span><span />
<span>r = - d [A] / dt = k[A]
</span><span />
<span>2) When you integrate you get:
</span><span />
<span> [ A] = Ao x e ^(-kt)
</span><span />
Remember that here A is PH₃
<span>3) Plug in the data: Ao = 0.0316M, k = 0.0180 /s, and t = 99s
</span><span />
<span>[PH₃] = 0.0316 M x e ^( - 0.0180/s x 99s) = 5.32 x 10⁻³ M</span>
Answer:
One nucleophilic center
Explanation;
Nucleophile:
Nucleophile is a substance which is nucleus loving in nature (<em>Nucleo</em>; Nucleus , <em>phile</em>; Loving). It is known as a specie which donates a lone pair of electrons to electrophile (electron loving) in a chemical reaction.
Thus, Nucleophile is the region of higher electron density in a molecule and attacks on the lower electron density region of another molecule. Also, the nucleophile can also contain a negative charge.
Number of Nucleophilic centers in Methanol:
The chemical structure of Methanol is attached below and it can be observed that the oxygen atom is containing two lone pair of electrons. Hence, the oxygen atom can act as a nucleophilic center. Therefore, there is only one nucleophilic center in methanol.
H₃C-OH + H₃C-Br → H₃C-O-CH₃ + HBr
In above reaction methanol is acting as a nucleophile and is attacking on electrophilic center (Carbon) of methyl bromide yielding dimethyl ether.
Answer:
The answer to your question is Qt = 15750 cal
Explanation:
Data
mass = m = 150 g
Initial temperature = T1 = 0°C
Final temperature = T2 = 25°C
Process
1.- Calculate the Latent heat of fusion
Latent heat of fusion for water = l = 80 cal/g
Heat = Q
Formula
Q = ml
Substitution
Q = (150)(80)
Simplification and result
Q = 12000 cal
2.- Calculate the Specific heat
Specific heat of water = C = 1 cal/g°C
Formula
Q = mCΔT
Substitution
Q = (150)(1)(25 - 0)
Simplification and result
Q = 3750 cal
3.- Calculate the total heat
Qt = 12000 + 3750
Qt = 15750 cal
1) You neeed to know and use the Ksp for BaF2.
At 25°C this Ksp is 1.0 * 10 ^ - 6
2) The solutibility of BaF2 is given by:
BaF2 ⇄ Ba(2+) + 2F(-)
x 2x
=> Ksp = x * (2x)^2 = 4x^3
3) When you have a NaF solution, you have to take into accout the concentration of the NaF solution
M = 0.1
Now the equilibrium species are:
BaF2 ⇄ Ba(2+) + 2F(-)
x 2x + 0.10
And Ksp = x* [2x + 0.10]^2 = 1.0 * 10 ^ -6
Given that the Ksp << 1 you may assume that 2x << 0.1 => 2x + 0.1 ≈ 0.1
=> 1.0 * 10 ^ - 6 ≈ x(0.1)^2 = 0.01x
=> x = 1.0 * 10^ -6 / 0.01 = 1.0 * 10^ - 4 M = 0.0001 M
That is the molar solubility.
4) Now, you calculate the number of moles from the molarity's formula:
M = n / v => n = M * v = 0.0001 M * 0.500 l = 0.00005 mol
And now convert to grams,
mass in grams = number of moles * molar mass
molar mass of BaF2 = 175.34 g/mol
mass in grams = 0.00005 moles * 175.34 g / mol = 0.0088 g
Answer: 0.0088 g