Question

A
zero-order reaction is 40% complete at the end of 50 minutes. What
is the value id the rate constant with proper units? In many
minutes will the reaction be 80% complete?

Answer #1

Suppose the reaction is

A => B

Rate of reaction

Rate of disappearance of A (-r_{A})= Rate of formation
of B (+r_{B}) = k
........where k is rate constant

-dC_{A}/dt = k

-dC_{A}= kt

integrate the above equation in the limits C_{A0} to
C_{A} at t= 0 to t

So the integration within the limits wil give

C_{A0}- C_{A}= -kt

(C_{A0}= initial concentartion in mol/L of A at t=0
mins, C_{A}= concentartion of A in mol/L at t=t mins)

Now 40% of reaction went to completion in 50 mins.

Means the 40% of A is reacted to produce B in 50 mins.

So,

C_{A0}- C_{A} = C_{A0} - 0.60
C_{A0} = 0.40 C_{A0}

And t= 50 mins

So, put this in above equation

0.40 C_{A0} = -50k

k= - (0.40/50) C_{A0}

k= -8*10^{-3} C_{A0} mol/(L.min)

Now for 80% completion

C_{A0}-C_{A} = 0.80C_{A0}

Then,

0.80C_{A0} = -kt

0.80C_{A0} = - (-8*10^{-3}) C_{A0 *}
t

t= 100 mins

So in 100 mins reacion will be 80% complete.

The decomposition of X is the first-order reaction.
After 60 minutes, X loses its 50% in weight. Find the time it takes
to lose 80%.

Experiments have shown the following reaction to be zero order
with a rate constant = 3.10 10-1 M/sec. A → B + 2 C If you started
with [A] = 3.000 M, how many minutes until the concentration of A =
2.442 M? I already found the answer to this to be 0.03 minutes but
cannot figure out the second part below How many minutes until the
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The integrated rate laws for zero-, first-, and second-order
reaction may be arranged such that they resemble the equation for a
straight line,y=mx+b.
Order
Integrated Rate Law
Graph
Slope
0
[A]=−kt+[A]0
[A] vs. t
−k
1
ln[A]=−kt+ln[A]0
ln[A] vs. t
−k
2
1[A]= kt+1[A]0
1[A] vs. t
k
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The reactant concentration in a zero-order reaction was
5.00×10−2M after 200 s and
2.50×10−2M after 310 s . What is the rate
constant for this reaction?
Express your answer with...

The integrated rate laws for zero-, first-, and second-order
reaction may be arranged such that they resemble the equation for a
straight line,y=mx+b.
Order
Integrated Rate Law
Graph
Slope
0
[A]=−kt+[A]0
[A] vs. t
−k
1
ln[A]=−kt+ln[A]0
ln[A] vs. t
−k
2
1[A]= kt+1[A]0
1[A] vs. t
k
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8.00×10−2M after 200 s and
2.50×10−2Mafter 390 s . What is the rate
constant for this reaction?
Express your answer with the...

The integrated rate laws for zero-, first-, and second-order
reaction may be arranged such that they resemble the equation for a
straight line,y=mx+b.
Order
Integrated Rate Law
Graph
Slope
0
[A]=−kt+[A]0
[A] vs. t
−k
1
ln[A]=−kt+ln[A]0
ln[A] vs. t
−k
2
1[A]= kt+1[A]0
1[A] vs. t
k
Part A
The reactant concentration in a zero-order reaction was
7.00×10−2M after 135 s and
2.50×10−2M after 315 s . What is the rate
constant for this reaction?
Express your answer with...

The integrated rate laws for zero-, first-, and second-order
reaction may be arranged such that they resemble the equation for a
straight line,y=mx+b.
Order
Integrated Rate Law
Graph
Slope
0
[A]=−kt+[A]0
[A] vs. t
−k
1
ln[A]=−kt+ln[A]0
ln[A] vs. t
−k
2
1[A]= kt+1[A]0
1[A] vs. t
k
------------
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4.00×10−2M after 375 s . What is the rate
constant for this reaction?
----------
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The integrated rate laws for zero-, first-, and second-order
reaction may be arranged such that they resemble the equation for a
straight line,y=mx+b.
1.) The reactant concentration in a zero-order reaction was
6.00×10−2M after 165 s and
3.50×10−2Mafter 385 s . What is the rate
constant for this reaction?
2.)What was the initial reactant concentration for the reaction
described in Part A?
3.)The reactant concentration in a first-order reaction was
6.70×10−2
M after 40.0 s and 2.50×10−3Mafter
95.0 s ....

Part A
A certain first-order reaction (A→products) has a rate constant
of 7.20×10−3 s−1 at 45 ∘C. How many minutes does it take
for the concentration of the reactant, [A], to drop to 6.25% of the
original concentration?
Express your answer with the appropriate units.
Answer:
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Part B
A certain second-order reaction (B→products) has a rate constant
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A) 3.8 10–2 mol/L • s
B) 1.5 10–11 mol/L • s
C) 8.1 10–4 mol/L • s
D) 2.2 10–3 mol/L • s
E) 8.4 ...

For a first-order reaction, the half-life is constant. It
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t1/2=1k[A]0
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A certain first-order reaction (A→products) has a rate constant
of 4.20×10−3 s−1 at 45 ∘C. How many minutes does it take
for the concentration of the reactant, [A],...

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