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3 years ago

PREDICT Why do you think energy must be added to change carbon powder into a synthetic diamond?

Chemistry

1 answer:

timurjin [86]3 years ago

3 0

Explanation:

Energy must be added to change carbon powder into synthetic diamond because at ordinary temperature and pressure conditions, this reaction will not take place.

To form diamond, conditions of high pressure must be made available. Diamond is an allotrope of carbon that is very hard and difficult to break.

To form diamond synthetically, we must be able to replicate the natural conditions by which it forms.

Diamond forms under very high grade metamorphic pressure. This must also be the condition to form the synthetic variant.

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CaCl2 (picture) i don’t know how to do the problem

Vadim26 [7]

Answer:

Ca: 1

Cl: 2

Explanation:

Since there is no subscript but there is the element, its assumed that there is at least 1, otherwise it would'nt be there

8 0

4 years ago

A sample of an unknown gas takes 222 s to diffuse through a porous plug at a given temperature. At the same temperature, N2(g) t

gulaghasi [49]

Answer:

$\large \boxed{\text{45.1 g/mol}}$

Explanation:

Graham’s Law applies to the diffusion of gases:

The rate of diffusion (r) of a gas is inversely proportional to the square root of its molar mass (M).

$r \propto \dfrac{1}{\sqrt{M}}$

If you have two gases, the ratio of their rates of diffusion is

$\dfrac{r_{2}}{r_{1}} = \sqrt{\dfrac{M_{1}}{M_{2}}}$

The time for diffusion is inversely proportional to the rate.

$\dfrac{t_{2}}{t_{1}} = \sqrt{\dfrac{M_{2}}{M_{1}}}$

Data:

t₂ = 222 s

t₁ = 175 s

M₁ = 28.01

Calculation :

$\begin{array}{rcl}\dfrac{222}{175} & = & \sqrt{\dfrac{M_{2}}{28.01}}\\\\1.269 & = & \sqrt{\dfrac{M_{2}}{28.01}}\\\\1.609 & = & \dfrac{M_{2}}{28.01}\\\\M_{2} & = & 1.609 \times 28.01\\ & = & \textbf{45.1 g/mol}\\\end{array}\\\text{The molar mass of the unknown gas is $\large \boxed{\textbf{45.1 g/mol}}$}$

3 0

3 years ago

calculate the molar mass of nickel (iii)oxide to the nearest tenth place. Give both the numerial value and the units

maksim [4K]

Nickel (Ni) has the charge as +3 while oxygen (O) has -2. Hence, the chemical formula for the nickel (iii) oxide is Ni₂O₃.

molar mass of Ni = 58.69 g/mol
molar mass of O = <span>15.99 g/mol

number of Ni atoms in </span>Ni₂O₃ = 2
Molar mass of Ni in Ni₂O₃ = 2 x 58.69 g/mol = 117.38 g/mol

number of O atoms in Ni₂O₃ = 3
Molar mass of O in Ni₂O₃ = 3 x 15.99 g/mol = 47.97 g/mol

Hence, molar mass of compound = 117.38 g/mol + 47.97 g/mol
= 165.35 g/mol
=<span> 165.4 g/mol</span>

8 0

4 years ago

What is the difference between nitrite and nitrate

Dahasolnce [82]

Answer:

<u>Nitrite:</u>

Formula : NO₂⁻
1 nitrogen molecule and two oxygen molecules with an excess electron.
Angular shape

<u>Nitrate:</u>

Formula: NO₃⁻

1 nitrogen molecule and three oxygen molecules with an excess electron.
Trigonal planar structure.

$\rule[225]{225}{2}$

Hope this helped!

4 0

2 years ago

What volume of CH4(g), measured at 25oC and 745 Torr, must be burned in excess oxygen to release 1.00 x 106 kJ of heat to the su

anastassius [24]

Answer:

$V=27992L=28.00m^3$

Explanation:

Hello,

In this case, the combustion of methane is shown below:

$CH_4+2O_2\rightarrow CO_2+2H_2O$

And has a heat of combustion of −890.8 kJ/mol, for which the burnt moles are:

$n_{CH_4}=\frac{-1.00x10^6kJ}{-890.8kJ/mol}= 1122.6molCH_4$

Whereas is consider the total released heat to the surroundings (negative as it is exiting heat) and the aforementioned heat of combustion. Then, by using the ideal gas equation, we are able to compute the volume at 25 °C (298K) and 745 torr (0.98 atm) that must be measured:

$PV=nRT\\\\V=\frac{nRT}{P}=\frac{1122.6mol*0.082\frac{atm*L}{mol*K}*298K}{0.98atm}\\\\V=27992L=28.00m^3$

Best regards.

8 0

4 years ago