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scZoUnD [109]
3 years ago
6

Erbium (Er) is element 68 on the periodic table. A sample contains 5.04×1023 atoms of Er. Calculate the amount of Er.

Chemistry
1 answer:
Korvikt [17]3 years ago
3 0

Answer:

139.98 g to nearest hundredth.

Explanation:

Using Avogadro's Number:

One mole (167.26 g) of Erbium  equates to  6.022141 * 10^23 atoms.

So 5.04 * 10^23 = 167.26 * 5.04/6.022141

= 139,98 g.

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For the reaction o(g) + o2(g) → o3(g) δh o = −107.2 kj/mol given that the bond enthalpy in o2(g) is 498.7 kj/mol, calculate the
Aneli [31]
The reaction;
O(g) +O2(g)→O3(g), ΔH = sum of bond enthalpy of reactants-sum of food enthalpy of products.
ΔH = ( bond enthalpy of O(g)+bond enthalpy of O2 (g) - bond enthalpy of O3(g)
-107.2 kJ/mol = O+487.7kJ/mol =O+487.7 kJ/mol +487.7kJ/mol =594.9 kJ/mol
Bond enthalpy (BE) of O3(g) is equals to 2× bond enthalpy of O3(g) because, O3(g) has two types of bonds from its lewis structure (0-0=0).
∴2BE of O3(g) = 594.9kJ/mol
Average bond enthalpy = 594.9kJ/mol/2
=297.45kJ/mol
∴ Averange bond enthalpy of O3(g) is 297.45kJ/mol.
8 0
3 years ago
Calculate the number of moles of H2 produced in the reaction of Mg(s) with HCl(aq). Mg(s) is the
Taya2010 [7]

Explanation:

Moles of metal,

=

4.86

⋅

g

24.305

⋅

g

⋅

m

o

l

−

1

=

0.200

m

o

l

.

Moles of

H

C

l

=

100

⋅

c

m

−

3

×

2.00

⋅

m

o

l

⋅

d

m

−

3

=

0.200

m

o

l

Clearly, the acid is in deficiency ; i.e. it is the limiting reagent, because the equation above specifies that that 2 equiv of HCl are required for each equiv of metal.

So if

0.200

m

o

l

acid react, then (by the stoichiometry), 1/2 this quantity, i.e.

0.100

m

o

l

of dihydrogen will evolve.

So,

0.100

m

o

l

dihydrogen are evolved; this has a mass of

0.100

⋅

m

o

l

×

2.00

⋅

g

⋅

m

o

l

−

1

=

?

?

g

.

If 1 mol dihydrogen gas occupies

24.5

d

m

3

at room temperature and pressure, what will be the VOLUME of gas evolved?

5 0
2 years ago
How many miles can you drive, if your car gets 21.3 miles per gallon and you have 12.0 gallons of gas?
Travka [436]

Answer:

255.6

Explanation:

If you have 12 gallons and get 21.3mpg,

-Multiply 21.3 by 12

-you can travel 255.6 miles before running out of gas.

-If you need to estimate, round up to 256 miles.

6 0
3 years ago
How important is it for scientists and engineers to be able to control the design of
Hatshy [7]

It is important for scientists and engineers to be able to control the design of the material because<u> it create solutions to problems</u>.

<h3>Why material science and engineering is important?</h3>

What things are made of and why they behave the way they do are lessons we learn from materials science. Materials engineering teaches us how to use knowledge to improve things and the way they are made. Research and industry innovation in fields as diverse as aerospace and medicine are driven by materials science and engineering.

<h3>Why is it important for scientists to use the scientific method?</h3>

The scientific method is essential because: It follows a set of rules. Scientists conduct experiments in a standardized manner because the steps used in the scientific method are systematic. This suggests that their research might be spread widely.

To know more about aerospace :

brainly.com/question/27182063

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4 0
1 year ago
If you start with 6 moles of N2 and 6 moles of H2 (meaning you won't have enough of 1 of the ingredients), how many moles of NH3
Ivahew [28]

Answer:

4molNH_3

Explanation:

Hello there!

In this case, according to the given information it will be firstly necessary to set up the chemical equation taking place:

N_2+3H_3\rightarrow 2NH_3

We infer we need to calculate the moles of NH3 by using both of the moles of N2 and H2 at the beginning, in order to identify the limiting reactant:

n_{NH_3}=6molN_2*\frac{2molNH_3}{1molN_2}=12molNH_3\\\\ n_{NH_3}=6molH_2*\frac{2molNH_3}{3molH_2}=4molNH_3\\

Thus, since hydrogen yields the fewest moles of ammonia, we conclude that we are just able to yield 4 moles of NH3.

Regards!

8 0
3 years ago
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