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2 years ago

10

Please work out all the problems on this page, no links, no i don't knows please do not take advantage of me or my points please

actually answer these questions

2 answers:

Alexxandr [17]2 years ago

4 0

Answer:

Explanation:

SOLID-LIQUID-GAS

dimaraw [331]2 years ago

3 0

Solid-liquid-gas I’m pretty sure!((:

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How many neutrons does element X have if its atomic number is 31 and its mass number is 80?

MrRissso [65]

49 neutrons in each nucleus.

<h3>Explanation</h3>

For each nucleus:

Mass number = Number of protons + Number of neutrons.

The atomic number of a nucleus is the same as its number of protons. The atomic number of the nucleus here is 31. There are 31 protons in each nucleus.

Mass number = 80;
Number of protons = Atomic number = 31;
The number of neutrons is to be found.

Again,

Mass number = Number of protons + Number of neutrons.

80 = 31 + Number of neutrons.

Number of neutrons = 80 - 31 = 49.

5 0

2 years ago

Most of the costs associated with using renewable resources are due to

saveliy_v [14]

Answer:

a. overuse of resources is the correct answer.

Explanation:

Renewable resources are available and they are abundant but overuse of these renewable resources will have a negative effect on the surroundings and humans.

Overuse of renewable resources will leads to the depletion of these renewable sources in the future and will also make the ecosystem unbalance.

Renewable resources are solar energy, geothermal energy, biomass energy, wind energy, hydro energy.

Thus renewable resources are threatened due to overuse and it must be carefully used.

6 0

3 years ago

How long does it take to electroplate 0.5 mm of gold on an object with a surface area of 31 cm^^ from an Au3+(aq) solution with

konstantin123 [22]

Answer:

It will take 5492 seconds to electroplate 0.5 mm of gold on an object .

Explanation:

Mass of gold = m

Volume of gold = v

Surface area on which gold is plated = $a=31 cm^2$

Thickness of the gold plating = h = 0.5 mm = 0.05 cm

1 mm = 0.1 cm

$V=a\times h=31 cm^2\times 0.05 cm=1.55 cm^3$

Density of the gold = $d=19.3 g/cm^3$

$m=d\times v=19.3 g/cm^3\times 1.55 cm^3=29.915g$

Moles of gold = $\frac{29.915 g}{197 g/mol}=0.152 mol$

$Au^{3+}+3e^-\rightarrow Au$

According to reaction, 1 mole of gold required 3 moles of electrons,then 0.152 moles of gold will require :

$\frac{3}{1}\times 0.152 mol=0.456 mol$ of electrons

Number of electrons = N = $0.456\times \times 6.022\times 10^{23}$

Charge on single electron = $q=1.6\times 10^{-19} C$

Total charge required = Q

$Q=N\times q$

Amount of current passes = I = 8 Ampere

Duration of time = T

$I=\frac{Q}{T}$

$T=\frac{N\times q}{I}$

$=\frac{0.456\times \times 6.022\times 10^{23}\times 1.6\times 10^{-19} C}{8 A}=5492 s$

It will take 5492 seconds to electroplate 0.5 mm of gold on an object .

7 0

2 years ago

What is the mass of 5 mole of ammonia . Calculate the number of NH₃ molecules, nitrogen atom and hydrogen atoms in it..

Aloiza [94]

Molar mass of NH_3

$\\ \sf\longmapsto 14u+3(1u)$

$\\ \sf\longmapsto 14u+3u$

$\\ \sf\longmapsto 17g/mol$

We know.

No of moles=Given mass/Molar mass

$\\ \sf\longmapsto Given\;Mass=17(5)$

$\\ \sf\longmapsto Given \:Mass\:of\:NH_3=85g$

Now

Lets write the balanced equation

$\\ \sf\longmapsto N_2+3H_2=2NH_3$

There is 2moles of Ammonia
3moles of H_2
1mole of N_2

Now

$\boxed{\sf No\:of\:Molecules =No\:of\;moles\times Avagadro\:no}$

For Hydrogen

$\\ \sf\longmapsto 3\times 6.023\times 10^{23}$

$\\ \sf\longmapsto 18.069\times 10^{23}$

$\\ \sf\longmapsto 1.8\times 10^{22}molecules$

For Ammonia

$\\ \sf\longmapsto 2\times 6.023\times 10^{23}$

$\\ \sf\longmapsto 12.046\times 10^{23}$

$\\ \sf\longmapsto 1.2\times 10^{22}molecules$

For Nitrogen

$\\ \sf\longmapsto 1\times 6.023\times 10^{23}$

$\\ \sf\longmapsto 6.023\times 10^{23}molecules$

3 0

2 years ago

Match the following vocabulary words with their definitions.

omeli [17]

1. condensation
2. evaporation
3. precipitation
4. transpiration
5. dew

6 0

2 years ago

Read 2 more answers