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almond37 [142]
2 years ago
6

A certain first-order reaction a → b is 25% complete in 42 min at 25°c. What is the half-life of the reaction?.

Chemistry
1 answer:
kicyunya [14]2 years ago
8 0

Half life of the reaction is :-101.9 min

a→b

25% reacted means 75% remains

t=42 min

Rate constant

k=(2.303/t)(log a/a-x)

k=(2.303/42)(log 100/100-25 )

k=(0.054) (log 100/75)

k=(0.054)(0.1249)

k=0.0068per min

half life

t1/2=(0.693/k)

     =(0.693/0.0068)

     =101.9 min

Learn more about Half life here:-

brainly.com/question/3788119

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Which wave has a disturbance that is perpendicular to the wave motion?
RideAnS [48]

transverse wave

A transverse wave is a wave in which particles of the medium move in a direction perpendicular to the direction that the wave moves.

3 0
3 years ago
Iron is biologically important in the transport of oxygen by red blood cells from the lungs to the various organs of the body. I
Aneli [31]

Answer : The number of iron atoms present in each red blood cell are, 1.077\times 10^9

Explanation :

First we have to calculate the moles of iron.

\text{Moles of iron}=\frac{\text{Mass of iron}}{\text{Molar mass of iron}}=\frac{2.90g}{55.85g/mole}=0.0519moles

Now we have to calculate the number of iron atoms.

As, 1 mole of iron contains 6.022\times 10^{23} number of iron atoms

So, 0.0519 mole of iron contains 0.0519\times 6.022\times 10^{23}=3.125\times 10^{22} number of iron atoms

Now we have to calculate the number of iron atoms are present in each red blood cell.

Number of iron atoms are present in each red blood cell = \frac{\text{Number of iron atoms}}{\text{Total number of red blood cells}}

Number of iron atoms are present in each red blood cell = \frac{3.125\times 10^{22}}{2.90\times 10^{13}}

Number of iron atoms are present in each red blood cell = 1.077\times 10^9

Therefore, the number of iron atoms present in each red blood cell are, 1.077\times 10^9

6 0
3 years ago
All of the substances on the periodic table are classified as elements except
zzz [600]

Answer: all elements in the periodic table is classified as elements

Explanation:

The structure of the table shows periodic trends. The seven rows of the table, called periods, generally have metals on the left and nonmetals on the right. The columns, called groups, contain elements with similar chemical behaviours. Six groups have accepted names as well as assigned numbers: for example, group 17 elements are the halogens; and group 18 are the noble gases

6 0
3 years ago
How many grams of methane gas (CH4) need to be combusted to produce 12.5 L water vapor at 301 K and 1.1 atm? Show all of the wor
tangare [24]
Answer is: 4.45 grams of methane gas <span>need to be combusted</span>.
Balanced chemical reaction: CH₄ + 2O₂ → CO₂ + 2H₂O.
Ideal gas law: p·V = n·R·T.<span>
p = 1.1 atm.
T = 301 K.
V(H</span>₂O) <span>= 12.5 L.
R = 0,08206 L·atm/mol·K.
</span>n(H₂O) = <span>1.1 atm · 12.5 L ÷ 0,08206 L·atm/mol·K · 301 K.
</span>n(H₂O) = 0.556 mol.
From chemical reaction: n(H₂O) : n(CH₄) = 2 : 1.
n(CH₄) = 0.556 mol ÷ 2 = 0.278 mol.
m(CH₄) = 0.278 mol · 16 g/mol.
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3 years ago
Which of the following are excited in ultraviolet photoelectron spectroscopy?
zavuch27 [327]

Answer:

D. Valance Electrons

Explanation:

6 0
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