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Consider 2H2 + O2 → 2H2O. To produce 1.2 g water, how many grams of H2 are required? Report to the correct number of significant

Elden [556K]

Answer:

0.133 mol (corrected to 3 sig.fig)

Explanation:

Take the atomic mass of H=1.0, and O=16.0,

no. of moles = mass / molar mass

so no. of moles of H2O produced = 1.2 / (1.0x2+16.0)

= 0.0666666 mol

From the equation, the mole ratio of H2:H2O = 2:2 = 1:1,

meaning every 1 mole of H2 reacted gives out 1 mole of water.

So, the no, of moles of H2 required should equal to the no, of moles of H2O produced, which is also 0.0666666 moles.

mass = no. of moles x molar mass

hence,

mass of H2 required = 0.066666666 x (1.0x2)

= 0.133 mol (corrected to 3 sig.fig)

3 0

3 years ago

The reaction 2a → a2 was experimentally determined to be second order with a rate constant, k, equal to 0.0265 m–1min–1. if

katovenus [111]

The integrated rate law for a second-order reaction is given by:

$\frac{1}{[A]t} = \frac{1}{[A]0} + kt$

where, [A]t= the concentration of A at time t,

[A]0= the concentration of A at time t=0

<span>k =</span> the rate constant for the reaction

<u>Given</u>: [A]0= 4 M, k = 0.0265 m–1min–1 and t = 180.0 min

Hence, $\frac{1}{[A]t} = \frac{1}{4} + (0.0265 X 180)$

<span><span><span>Therefore, [A]</span>t</span>= 0.2058 M.</span>

<span>Answer: C</span>oncentration of A, after 180 min, is 0.2058 M

7 0

3 years ago

Read 2 more answers

A solution contains 0.140 mol KCl in 2.100 L water. What is the concentration of KCl in g/L?

viva [34]

<h3><u>Answer</u>;</h3>

≈ 4.95 g/L

<h3><u>Explanation;</u></h3>

The molar mass of KCl = 74.5 g/mole

Therefore; 0.140 moles will be equivalent to ;

= 0.140 moles × 74.5 g/mole

= 10.43 g

Concentration in g/L

= mass in g/volume in L

= 10.43/2.1

= 4.9667

4 0

3 years ago

Strontium-90 is a radioisotope that will decrease in mass by one-half every 29 years. How many years will it take for a 10.0-gra

Lelechka [254]

Answer: It will take 29 years for a 10.0-gram sample of strontium-90 to decay to 5.00 grams

Explanation:

Radioactive decay process is a type of process in which a less stable nuclei decomposes to a stable nuclei by releasing some radiations or particles like alpha, beta particles or gamma-radiations. The radioactive decay follows first order kinetics.

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

Half life is represented by $t_{\frac{1}{2}$

$t_{\frac{1}{2}=\frac{0.693}{\lambda}$

$\lambda$ = rate constant

Given : Strontium-90 decreases in mass by one-half every 29 years , that is half life of Strontium-90 is 29 years.

As half life is independent of initial concentration, it will take 29 years for a 10.0-gram sample of strontium-90 to decay to 5.00 grams as the amount gets half.

7 0

3 years ago

A natural sample of boron consists of two isotopes

amid [387]

Boron: isotope data. Both isotopes ofBoron, B-10 and B-11, are used extensively in the nuclear industry. B-10 is used in the form of boric acid as a chemical shim in pressurized water reactors while in the form of sodium pentaborate it is used for standby liquid control systems in boiling water reactors

7 0

3 years ago