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3 years ago

Once an atom has full s and p orbitals in its outermost energy level is it stable or unstable?

Chemistry

1 answer:

stich3 [128]3 years ago

4 0

A table decreased in price by
3
5
. After the reduction it was priced at £40. What was the original price of the table?

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True or false atoms with fewer then 4 outer elections lend elections?

Mamont248 [21]

The answer is false ....

3 0

3 years ago

The reaction of hydrogen gas and iron oxide is described by the chemical equation below. 3H2+Fe2O3→2Fe+3H2O How many moles of ir

ELEN [110]

Answer:

2.2 moles of Fe will be produced

Explanation:

Step 1: Data given

Number of moles of hydrogen gas = 3.3 moles

Number of moles of iron oxide = 1.5 moles

Step 2: The balanced equation

3H2 + Fe2O3 → 2Fe + 3H2O

Step 3: Calculate the limiting reactant

For 3 moles H2 we need 1 mol Fe2O3 to produce 2 moles Fe and 3 moles H2O

Hydrogen gas is the limiting reactant. It will completely be consumed (3.3 moles). Fe2O3 is in excess. There will react 3.3 / 3 = 1.1 moles

There will remain 1.5 - 1.1 = 0.4 moles Fe2O3

Step 4: Calculate moles Fe

For 3 moles H2 we need 1 mol Fe2O3 to produce 2 moles Fe and 3 moles H2O

For 3.3 moles H2 we'll have 2/3 * 3.3 = 2.2 moles Fe

2.2 moles of Fe will be produced

5 0

3 years ago

As a forensic expert, Jane needs to handle many biological evidence samples simultaneously. What is the basic precaution that sh

madreJ [45]

Answer:

B. use a new pair of gloves for each piece of evidence

Explanation:

When it comes to the basic precautions of handling biological evidence samples, one has to prevent cross contamination. This refers to the<em> transfer of DNA from one evidence to another evidence</em>; thus, it is important for Jane to use a new pair of gloves for each piece of evidence in order to prevent such occurrence.

Wearing of gloves will also <em>prevent Jane's DNA from being implanted into the sample</em>, and it will keep her safe from contracting blood-borne pathogens like those in the saliva, blood or semen.

7 0

3 years ago

1 mol super cooled liquid water transformed to solid ice at -10 oC under 1 atm pressure.

Arada [10]

Answer:

Explanation:

Given that:

number of moles of super cooled liquid water = 1

Melting enthalpy of ice = 6020 J/mol

Freezing point =0 °C = (0 + 273 K)= 273 K

The decrease in entropy of the system during freezing for 1 mol (i.e during transformation from liquid water to solid ice ) = - 6020 J/mol × 1 mol /273 K = -22.051 J/K

Entropy change during further cooling from 0 °C (273 K) to -10 °C (263 K)

$\Delta \ S = \int\limits^{T_2}_{T_1}\dfrac{nC_p(s)dT}{T}$

$\Delta \ S = {nC_p(s)In \dfrac{T_2}{T_1}$

$\Delta \ S = {(1*37.7)In \dfrac{263}{273}$

Δ S = -1.4 J/K

Total entropy change of the system = - 22.05 J/K - 1.4 J/K = - 23.45 J/K

Entropy change of universe = entropy change of the system+ entropy change of the surrounding

According to the second law of thermodynamics

Entropy change of universe >0

SO,

Entropy change of the system + entropy change in the surrounding > 0

Entropy change in the surrounding > - entropy change of the system

Entropy change in the surrounding > - (- 23.53 J/K)

Entropy change in the surrounding > 23.53 J/K

b) Make some comments on entropy changes from the obtained data.

From the data obtained; we will realize that the entropy of the system decreases as cooling takes place when water is be convert to ice , randomness of these molecules reduces and as cooling proceeds , hence, entropy reduces more as well and the liberated heat will go into the surrounding due to this entropy of the surrounding increasing.

4 0

2 years ago

For the reaction 6 Li + N2 → 2 Li3N , what is the maximum amount of Li3N (34.8297 g/mol) which could be formed from 14.18 mol (6

Yuki888 [10]

Moles Li = 3.50 g / 6.941 g/mol= 0.504
the ratio between Li and N2 is 6 : 1
moles N2 required = 0.504 /6=0.0840
we have 3.50 g / 28.0134 g/mol=0.125 moles of N2 so N2 is in excess
the ratio between Li and Li3N is 6 : 2
moles Li3N = 0.504 x 2 /6=0.168
mass Li3N = 0.168 mol x 34.8297 g/mol=5.85 g

4 0

3 years ago