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3 years ago

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Magnesium hydroxide is 54.87% oxygen by mass.

1 answer:

ira [324]3 years ago

5 0

Answer:

hhmxui

Explanation:

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How can a scientist ensure that his or her data are reliable? by making a single observation

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Having accurate Specific date can give scientist what they need for more reliabliltiy.

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3 years ago

Read 2 more answers

A reaction has activation energy of 85kjper mol. What is the effect on the rate of raising the temperature from 20degree to 30 d

DENIUS [597]

Answer: The rate increases 3 times on raising the temperature from 20degree to 30 degree

Explanation:

According to Arrhenius equation with change in temperature, the formula is as follows.

$ln \frac{k_{2}}{k_{1}} = \frac{-E_{a}}{R}[\frac{1}{T_{2}} - \frac{1}{T_{1}}]$

where $k_2$ = rate constant at temp $T_2$

$k_1$ = rate constant at temp $T_1$

$E_a$ = activation energy

R= gas constant

$T_1$ = temperature = $20^0C=(20+273)K=293K$

$T_2$ = temperature = $30^0C=(30+273)K=303K$

$ln \frac{k_{2}}{k_{1}} = \frac{-85\times 1000J/mol}{8.314J/Kmol}[\frac{1}{303} - \frac{1}{293}]$

$ln \frac{k_{2}}{k_{1}}=1.15$

$\frac{k_{2}}{k_{1}}=3$

Thus rate increases 3 times on raising the temperature from 20degree to 30 degree

3 0

3 years ago

An ideal gas in a cylindrical container of radius r and height h is kept at constant pressure p. The bottom of the container is

Juli2301 [7.4K]

Answer:

$m =\frac{p*(pi)*r^{2}*h*mw}{R*\frac{T_{1} + T_{O}}{2}}$

Explanation:

The gas ideal law is

PV= nRT (equation 1)

Where:

P = pressure

R = gas constant

T = temperature

n= moles of substance

V = volume

Working with equation 1 we can get

$n =\frac{PV}{RT}$

The number of moles is mass (m) / molecular weight (mw). Replacing this value in the equation we get.

$\frac{m}{mw} =\frac{PV}{RT}$ or

$m =\frac{P*V*mw}{R*T}$ (equation 2)

The cylindrical container has a constant pressure p

The volume is the volume of a cylinder this is

$V =(pi)*r^{2}*h$

Where:

r = radius

h = height

(pi) = number pi (3.1415)

This cylinder has a radius, r and height, h so the volume is $V =(pi)*r^{2}*h$

Since the temperatures has linear distribution, we can say that the temperature in the cylinder is the average between the temperature in the top and in the bottom of the cylinder. This is:

$T =\frac{T_{1} + T_{O}}{2}$

Replacing these values in the equation 2 we get:

$m =\frac{P*V*mw}{R*T}$ (equation 2)

$m =\frac{p*(pi)*r^{2}*h*mw}{R*\frac{T_{1} + T_{O}}{2}}$

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3 years ago

Kendra conducts an experiment. She mixes two chemicals, resulting in a chemical reaction. Based on Kendra's

kondaur [170]

Answer: It changed in identity and properties.

Explanation:

3 0

3 years ago

A sample of a compound of xenon and fluorine contains molecules of a single type; XeFn, where n is a whole number. If 5.0 x 1020

kicyunya [14]

Answer:

4

Explanation:

Avogadro’s number represent the number of the constituent particles which are present in one mole of the substance. It is named after scientist Amedeo Avogadro and is denoted by $N_0$ .

Also, it is the number of particles in exactly 12.000 g of isotope carbon 12.

Avogadro constant:-

$N_a=6.023\times 10^{23}$

Hence,

Mass of $XeF_n$ = 131.293+ n18.998 g

So,

$6.023\times 10^{23}$ molecules have a mass of 131.293+ n18.998 g

Also,

$1$ molecules have a mass of $\frac{(131.293+ n18.998)}{6.023\times 10^{23}}$ g

So,

$5.0\times 10^{20}$ molecules have a mass of $\frac{(131.293+ n18.998)}{6.023\times 10^{23}}\times 5.0\times 10^{20}$ g

Also, given mass = 0.172 g

Thus,

$\frac{(131.293+ n18.998)}{6.023\times 10^{23}}\times 5.0\times 10^{20}=0.172$

$\frac{18.998n+131.293}{1204.6}=0.172$

$18.998n+131.293=207.1912$

$n=\frac{75.8982}{18.998}=4$

<u>Thus, value of n is 4.</u>

4 0

3 years ago