6. —K,Cr,0,+ --L1,0—<br> Combustion reaction

A first-order reaction is 45% complete at the end of 43 minutes. What is the length of the half-life of this reaction

shtirl [24]

The half-life of the reaction is 50 minutes

Data;

Time = 43 minutes
Type of reaction = first order
Amount of Completion = 45%

<h3>Reaction Constant</h3>

Let the initial concentration of the reaction be X $_0$

The reactant left = (1 - 0.45) X $_0$ = 0.55 X $_0$ = X

For a first order reaction

$\ln(\frac{x}{x_o}) = -kt\\ k = \frac{1}{t}\ln (\frac{x_o}{x}) \\ k = \frac{1}{43}\ln (\frac{x_o}{0.55_o})\\ k = 0.013903 min^-^1$

The half-life of a reaction is said to be the time required for the initial amount of the reactant to reach half it's original size.

$x = \frac{x_o}{2} \\t = t_\frac{1}{2} \\t_\frac{1}{2} = \frac{1}{k}\ln(\frac{x_o}{x_o/2})\\$

Substitute the values

$t_\frac{1}{2} = \frac{1}{k}\ln(2)=\frac{0.6931}{0.013903}\\t_\frac{1}{2}= 49.85 min = 50 min$

The half-life of the reaction is 50 minutes

Learn more on half-life of a first order reaction here;

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4 0

3 years ago

A beaker cost 8.40$and Harry drops 3 dozen beakers. How much will Harry's chemistry teacher charge

tatyana61 [14]

Answer:

302.40

Explanation:

i had the same question on a test

4 0

3 years ago

URGENT ! PLEASE ANSWER QUICKLY

Bumek [7]

Answer:If we dissolve NaF in water, we get the following equilibrium:

text{F}^-(aq)+text{H}_2text{O}(l) rightleftarrows text{HF}(aq)+text{OH}^-(aq)

The pH of the resulting solution can be determined if the K_b of the fluoride ion is known.

20.0 g of sodium fluoride is dissolve in enough water to make 500.0 mL of solution. Calculate the pH of the solution. The K_b of the fluoride ion is 1.4 × 10 −11 .

Step 1: List the known values and plan the problem.

Known

mass NaF = 20.0 g

molar mass NaF = 41.99 g/mol

volume solution = 0.500 L

K_b of F – = 1.4 × 10 −11

Unknown

pH of solution = ?

The molarity of the F − solution can be calculated from the mass, molar mass, and solution volume. Since NaF completely dissociates, the molarity of the NaF is equal to the molarity of the F − ion. An ICE Table (below) can be used to calculate the concentration of OH − produced and then the pH of the solution.

Explanation:

7 0

3 years ago

Read 2 more answers

Arrange the following units in decreasing order: nm,km,pm,Dm,mm,m,cm,hm,gm

goblinko [34]

The units are nm (nano-meter), km (kilo-meter), pm (pico-meter), dm (decimeter), mm (millimeter), m (meter), cm (centimeter), hm (hectometer) and gm (gigameter). Now we can express each of these units in terms of m.

1 nm = $10^{-9}m$ , 1 Km = $10^{3}m$ 1 pm = $10^{-12}m$ , 1 dm = 0.1 m, 1 mm = 0.001 m, 1 cm = 0.01 m, 1 hm = 100 m, 1 gm = $10^{9} m$ . Thus the decreasing unit will be