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3 years ago

What is the Damkohler number? b) What is the significance of a system with a low Damkohler number?

Chemistry

1 answer:

elena-s [515]3 years ago

8 0

Explanation:

(a) A number which is dimensionless and provides us an estimate of the degree of conversion which can be achieved in CSTR, that is, continuous stirred tank reactor is known as Damkohler number.

This number is denoted as Da.

Mathematically, Da = $\frac{\text{reaction rate}}{\text{convection rate}}$

Da = $\frac{-rA \times V}{Fa_{o}}$

Now, for first order system, Da = $\frac{-rA \times V}{Fa_{o}}$

= $\frac{k \times CA_{o} \times V}{v \times CA_{o}}$ = Tk

where, rA = rate of reaction

V = volume of reactor

$Fa_{o}$ = molar flow rate of component A

k = rate constant

$CA_{o}$ = initial concentration of A

v = volumetric flow rate of A

T = residence time

(b) Since, from a given Damkohler number we can figure out the possible conversion of CSTR, that is, continuous stirred tank reactor.

So, if we have a low Damkohler number then the system will give us a less conversion formula. As the conversion is as follows.

X = $\frac{Da}{Da + 1}$

Hence, we can conclude that $Da \leq 0.1$ will give less than 10% conversion as calculated by using above formula.

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if i add 25 ml of water to 135 ml of a 0.25 M NaOH solution what will the molarity of the diluted solution be

DENIUS [597]

Answer:

0.21 M. (2 sig. fig.)

Explanation:

The molarity of a solution is the number of moles of the solute in each liter of the solution. The unit for molarity is M. One M equals to one mole per liter.

How many moles of NaOH in the original solution?

$n = c \cdot V$ ,

where

$n$ is the number of moles of the solute in the solution.
$c$ is the concentration of the solution. $c = 0.25 \;\text{M} = 0.25\;\text{mol}\cdot\textbf{L}^{-1}$ for the initial solution.
$V$ is the volume of the solution. For the initial solution, $V = 135\;\textbf{mL} = 0.135\;\textbf{L}$ for the initial solution.

$n = c\cdot V = 0.25\;\text{mol}\cdot\textbf{L}^{-1} \times 0.135\;\textbf{L} = 0.03375\;\text{mol}$ .

What's the concentration of the diluted solution?

$\displaystyle c = \frac{n}{V}$ .

$n$ is the number of solute in the solution. Diluting the solution does not influence the value of $n$ . $n = 0.03375\;\text{mol}$ for the diluted solution.
Volume of the diluted solution: $25\;\text{mL} + 135\;\text{mL} = 160\;\textbf{mL} = 0.160\;\textbf{L}$ .

Concentration of the diluted solution:

$\displaystyle c = \frac{n}{V} = \frac{0.03375\;\text{mol}}{0.160\;\textbf{L}} = 0.021\;\text{mol}\cdot\textbf{L}^{-1} = 0.021\;\text{M}$ .

The least significant number in the question comes with 2 sig. fig. Keep more sig. fig. than that in calculations but round the final result to 2 sig. fig. Hence the result: 0.021 M.

8 0

3 years ago

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One of the intermediates in the synthesis of glycine from ammonia, carbon dioxide, and methane is aminoacetonitrile, C2H4N2. The

sleet_krkn [62]

Answer:

Mass of C₂H₄N₂ produced = 3.64 g

Explanation:

The balanced chemical equation for the reaction is given below:

3CH₄ (g) + 5CO₂ (g) + 8NH₃ (g) → 4C₂H₄N₂ (g) + 10H₂O (g)

From the equation, 3 moles of CH₄ reacts with 5 moles of CO₂ and 8 moles of NH₃ to produce 4 moles of C₂H₄N₂ and 10 moles of H₂O

Molar masses of the compounds are given below below:

CH₄ = 16 g/mol; CO₂ = 44 g/mol; NH3 = 17 g/mol; C₂H₄N₂ = 56 g/mol; H₂O g/mol

Comparing the mole ratios of the reacting masses;

CH₄ = 1.65/16 = 0.103

CO₂ = 13.5/44 = 0.307

NH₃ = 2.21/17 = 0.130

converting to whole number ratios by dividing with the smallest ratio

CH₄ = 0.103/0.103 = 1

CO₂ = 0.307/0.103 = 3

NH₃ = 0.130/0.103 = 1.3

Multiplying through with 5

CH₄ = 1 × 5 = 5

CO₂ = 3 × 5 = 15

NH₃ = 1.3 × 5 = 6.5

Therefore, the limiting reactant is NH₃

8 × 17 g (136 g) of NH₃ reacts to produce 4 × 56 g (224 g) of C₂H₄N₂

Therefore, 2.21 g of NH₃ will produce (2.21 × 224)/136 g of C₂H₄N₂ = 3.64 g of C₂H₄N₂

Mass of C₂H₄N₂ produced = 3.64 g

7 0

3 years ago

Is the number of total molecules on the left side of a balanced equation always equal to the number of total molecules on the ri

Nadya [2.5K]

Answer:

Explanation:

No, but the total mass of reactants must equal the total mass of products to be a balanced equation.

Example: Consider the following reaction ...

3H₂ + N₂ => 2NH₃ and 'amu' is atomic mass units (formula weights from periodic table)

In terms of molecules, there are 4 molecules on the left (3 molecular hydrogens (H₂) and 1 molecular nitrogen (N₂) and 2 molecules of ammonia on the right side of equation arrow. ∑reactant molecules ≠ ∑product molecules.

In terms of mass of reactants & mass of products, the 3H₂ + N₂ => 6amu + 28amu = 34amu & mass of products (2NH₃) => 2(14amu) + 6(1amu) = 34amu for sum of product masses.

∑mass reactants = ∑mass products <=> 34amu = 34amu.

The expression '∑mass reactants = ∑mass products' as applied to chemical equations is generally known as 'The Law of Mass Balance'.

3 0

3 years ago

Is the following reaction balanced or unbalanced?<br> 2Fe2O3 + 3C → 4Fe + 3CO2

crimeas [40]

Answer:

unbalanced

hope this helps

7 0

2 years ago

Assoli18 [71]

The answer should be d but it could be c

4 0

3 years ago

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