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2 years ago

True or False:

Chemistry

1 answer:

lesya [120]2 years ago

6 0

Answer:

False

Explanation:

Mendeleev was the first scientist to arrange the element in such a periodic order but there was a mistake that he arranged in increasing order of mass.
Today we use the periodic table given by Henry Mosley where atomic no is first priority

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A decomposition reaction has a half life of 578 years. (a) What is the rate constant for this reaction? (b) How many years does

maw [93]

Answer:

$0.001199 year^{-1}$ is the rate constant for this reaction.

It will take $1.73\times 10^3 years$ to concentration to reach 12.5% of its original value.

Explanation:

A decomposition reaction follows first order kinetics:

Half life of the reaction = $t_{1/2}=578 years$

Rate constant of the reaction = k

For first order reaction, half life and rate constant are linked with an expression :

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

$k=\frac{0.693}{578 years}=0.001199 year^{-1}$

$0.001199 year^{-1}$ is the rate constant for this reaction.

Initial concentration of reactant = $[A_o]$ = x

Final concentration of reactant after time t = $[A]$ = 12.5% of x = 0.125x

The integrated law of first order reaction :

$[A]=[A_o]\times e^{-kt}$

$0.125x=x\times e^{-0.001199 year^{-1}\times t}$

t = 1,734.31 years = $1.73\times 10^3 years$

It will take $1.73\times 10^3 years$ to concentration to reach 12.5% of its original value.

3 0

3 years ago

Select the correct answer.

Svetradugi [14.3K]

Answer:

the answer is A

Explanation:

According to the law of conservation of energy or the first law thermodynamics energy neither be created nor destroyed, energy is transferred from one form to another form.

4 0

3 years ago

Question 9 of 10

aksik [14]

Answer:

The answer is B an open system allows energy and mass to move in and out of it

Hope it helps

7 0

2 years ago

A) Find the gas speed of sulfur dioxide at 100.0 degrees Celsius? ______________

gtnhenbr [62]

a. 381.27 m/s

b. the rate of effusion of sulfur dioxide = 2.5 faster than nitrogen triiodide

<h3>Further explanation</h3>

Given

T = 100 + 273 = 373 K

Required

a. the gas speedi

b. The rate of effusion comparison

Solution

Average velocities of gases can be expressed as root-mean-square averages. (V rms)

$\large {\boxed {\bold {v_ {rms} = \sqrt {\dfrac {3RT} {Mm}}}}$

R = gas constant, T = temperature, Mm = molar mass of the gas particles

From the question

R = 8,314 J / mol K

T = temperature

Mm = molar mass, kg / mol

Molar mass of Sulfur dioxide = 64 g/mol = 0.064 kg/mol

$\tt v=\sqrt{\dfrac{3\times 8.314\times 373}{0.064} }\\\\v=381.27~m/s$

b. the effusion rates of two gases = the square root of the inverse of their molar masses:

$\rm \dfrac{r_1}{r_2}=\sqrt{\dfrac{M_2}{M_1} }$

M₁ = molar mass sulfur dioxide = 64

M₂ = molar mass nitrogen triodide = 395

$\tt \dfrac{r_1}{r_2}=\sqrt{\dfrac{395}{64} }=\dfrac{20}{8}=2.5$

the rate of effusion of sulfur dioxide = 2.5 faster than nitrogen triodide

4 0

3 years ago

Which of the following could be considered a scientific statement? (2 points)

Andrej [43]

Answer:

The answer of the scientific STATEMENT is" Appears That Ants Live In Colonies."

7 0

2 years ago