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3 years ago

When science is used to create a new instrument, such as a cell phone, we say that a new ___________ has been developed.

Chemistry

1 answer:

kari74 [83]3 years ago

3 0

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Suppose the half-life is 9.0 s for a first order reaction and the reactant concentration is 0.0741 M 50.7 s after the reaction s

bazaltina [42]

<u>Answer:</u> The time taken by the reaction is 84.5 seconds

<u>Explanation:</u>

The equation used to calculate half life for first order kinetics:

$k=\frac{0.693}{t_{1/2}}$

where,

$t_{1/2}$ = half-life of the reaction = 9.0 s

k = rate constant = ?

Putting values in above equation, we get:

$k=\frac{0.693}{9}=0.077s^{-1}$

Rate law expression for first order kinetics is given by the equation:

$k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}$ ......(1)

where,

k = rate constant = $0.077s^{-1}$

t = time taken for decay process = 50.7 sec

$[A_o]$ = initial amount of the reactant = ?

[A] = amount left after decay process = 0.0741 M

Putting values in equation 1, we get:

$0.077=\frac{2.303}{50.7}\log\frac{[A_o]}{0.0741}$

$[A_o]=3.67M$

Now, calculating the time taken by using equation 1:

$[A]=0.0055M$

$k=0.077s^{-1}$

$[A_o]=3.67M$

Putting values in equation 1, we get:

$0.077=\frac{2.303}{t}\log\frac{3.67}{0.0055}\\\\t=84.5s$

Hence, the time taken by the reaction is 84.5 seconds

6 0

3 years ago

It is desired to produce 2.25 grams of dichloromethane (CH2Cl2) by the following reaction. If the percent yield of dichlorometha

Allushta [10]

Answer:- 3.12 g carbon tetrachloride are needed.

Solution:- The balanced equation is:

$CH_4+CCl_4\rightarrow 2CH_2Cl_2$

From given actual yield and percent yield we will calculate the theoretical yield that would be further used to calculate the grams of carbon tetrachloride.

percent yield formula is:

percent yield = $(\frac{actual}{theoretical})100$

$65.5=(\frac{2.25}{theoretical})100$

$theoretical=(\frac{2.25(100)}{65.5})$

theoretical = 3.44 g

From balanced equation, there is 2:1 mol ratio between dichloethane and carbon tetrachloride.

Molar mass of dichloroethane is 84.93 gram per mol and molar mass of carbon tetrachloride is 153.82 gram per mol.

$3.44gCH_2Cl_2(\frac{1molCH_2Cl_2}{84.93gCH_2Cl_2})(\frac{1molCCl_4}{2molCH_2Cl_2})(\frac{153.82gCCl_4}{1molCCl_4})$

= $3.12gCCl_4$

So, 3.12 grams of carbon tetrachloride are needed to be reacted.

8 0

3 years ago

How do ice and water on the ground affect incoming solar radiation?

Rufina [12.5K]

Answer:

Ice and water on the ground affect incoming solar radiation by reflecting 4 percent of solar radiation that reaches the surface. ... When the sun angle is high and water is liquid notice, there is less reflection that takes place.

8 0

3 years ago

Read 2 more answers

Suppose that the C=O group in a peptide bond can be regarded as isolated from the rest of the molecule. Given that the force con

Stella [2.4K]

Answer:

a) v = 1497.2 cm^-1

b) v = 1465 cm^-1

Explanation:

In the attached image is the procedure explained to reach the answer.