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4 years ago

2. From each of the following pairs of atoms, pick the atom that has

Chemistry

1 answer:

Zina [86]4 years ago

7 0

Answer:

a) Na

c) Na

b) Sr

d) Ca

Explanation:

As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases because it is very difficult to remove the electron from atom and more energy is required.

As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.

As the size of atom increases the ionization energy from top to bottom also decreases because it becomes easier to remove the electron because of less nuclear attraction and as more electrons are added the outer electrons becomes more shielded and away from nucleus.

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Chlorofluorocarbons such as CCl2F and CCI,F, have been linked to ozone depletion in Antarctica. In 1994, these gases were found

Ilya [14]

Answer:

a) molarity of CCl3F = 1.12 × 10^-11 mol/dm³

Molarity of CCl2F2 = 2.20 × 10^-11 mol/dm³

B) molarity of CCL3F = 7.96 × 10 ^-13 mol/dm³

Molarity of CCl2F2 = 1.55 × 10^-12 mol/dm³

Explanation:

Using the ideal gas equation:

PV = nRT

Further explanations are found in the attachment below.

4 0

4 years ago

For the rxn CaCo3(s)+2Hcl(aq)_CaCl(aq)+Ca2(g)+H2O(l)68.1 g solid CaCo3 is mixed with 51.6Hcl what number of grams of Co2 will be

Svetach [21]

Answer:

29.9 g of CO₂ will be produced by the reaction.

Explanation:

This is the reaction:

CaCO₃(s) + 2HCl (aq) → CaCl₂(aq) + CO₂(g) + H₂O(l)

First of all, we state the moles of each reactant:

68.1 g . 1mol/ 100.08g = 0.680 mol of carbonate

51.6 g . 1 mol/36.45g = 1.46 mol of acid.

The solid salt is the limiting reactant. Ratio is 2:1

2 moles of acid can react to 1 mol of salt

1.46 mol of acid may react with (1.46 . 1)/2 = 0.727 moles

As we only have 0.680 moles of salt, we do not have enough.

Let's work at the product side. Ratio is 1:1

1 mo of salt can produce 1 mol of gas

0.680 moles will produce 0.680 moles of gas

We convert the moles to mass → 0.680 mol . 44g / 1mol = 29.9 g of CO₂

8 0

3 years ago

If an element is very reactive, is it more likely to be found in elemental state or in a compound?

tensa zangetsu [6.8K]

Answer:

Compound state

Explanation:

Because reactive elements mostly react immediately with other elements

5 0

3 years ago

A compound of carbon and hydrogen contains 92.3 percent c and has a molar mass of 78.1g/mol. What is its molecular

alekssr [168]

Answer:

C₆H₆

Explanation:

We need to find the molecular formula of a compound of carbon (C) and hydrogen (H), so what we need to find out is the number of atoms of C and of H in the molecule. We know:

molar mass = 78.1 g/mol
C% = 92.3% = 92.3 g C / 100 g compound

So, in 1 mol of compound, 92.3% of the mass corresponds to Carbon:

mass of C / mol of compound = molar mass × C% = 78.1 g/mol × 92.3/100 = 72.1 g/mol

moles of C = mass C / molar mass C = 72.1 g / 12.011 g/mol

moles of C = 6 moles of C per mol of compound

If 72.1 g in a mol of compound are Carbon atoms, the difference between the molar mass and the mass of Carbon atoms will correspond to H atoms in 1 mol of compound:

mass of H / mol of compound = molar mass - mass of C/mol

mass of H = 78.1 g / mol - 72.1 g /mol = 6.0 g/mol of compound

moles of H = mass H / molar mass H = 6.0 g / 1.008 g/mol

moles of H = 6.0 moles of H per mol of compound

So one mol of compound has 6 moles of C and 6 moles of H.

The molecular formula is then written as C₆H₆

7 0

3 years ago

What is the boiling point of cyclohexane at 620 mmhg? can you show calculations?

Anton [14]

Boiling point of cyclohexane at 620 mm hg?

Standard atmospheric pressure is 760 mm Hg. Boiling point at 760 mm= 80.74˚C

A liquid boils when its vapor pressure is equal to the atmospheric pressure. The vapor pressure of a liquid is proportional the absolute temperature of the liquid.

As the atmospheric pressure decreases, less vapor pressure is needed to cause the liquid to boil. Less vapor pressure means lower temperature.

The boiling point of cyclohexane at 620 mm Hg is less than 80.74˚C

TRY THAT OR THIS

271.78

7 0

3 years ago

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