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2 years ago

As the atomic numbers of the elements in column IIA increase, the size of the atoms generally

Chemistry

2 answers:

joja [24]2 years ago

7 0

Answer:

Increase

Explanation:

Gennadij [26K]2 years ago

7 0

Answer: The size of the atoms increases as the atomic number of the elements in Group II-A increases.

Explanation:

Atomic radius of an atom is defined as the total distance from the nucleus to the outermost shell of the atom.

On moving from top to bottom, an extra shell around the nucleus is added and the outermost shell gets far away from the nucleus and hence, the distance between the nucleus and outermost shell increases. Thus, increasing the atomic radii of the atom on moving from top to bottom.

We are given:

Atoms that are present in Group II-A are Beryllium (Z = 4), Magnesium (Z = 12), Calcium (Z = 20), Strontium (Z = 38), Barium (Z = 56) and Radium (Z = 88)

As, the atomic number increases on moving down the group, so does the atomic radius of the atoms in the group.

Hence, the size of the atoms increases as the atomic number of the elements in Group II-A increases.

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starting with methane ,name all the steps and write the equations involved in tetrachlorination.Remember all arrows sharing move

anygoal [31]

Answer:

See Explanation and image attached

Explanation:

Methane is an alkane. The commonest chemical reaction that alkanes undergo is substitution. During a substitution reaction, one or more atoms of hydrogen is/are replaced in the alkane.

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2 years ago

Hello, everyone!

marusya05 [52]

Answer: 27.09 ppm and 0.003 %.

First, for air pollutants, ppm refers to parts of steam or gas per million parts of contaminated air, which can be expressed as cm³ / m³. Therefore, we must find the volume of CO that represents 35 mg of this gas at a temperature of -30 ° C and a pressure of 0.92 atm.

Note: we consider 35 mg since this is the acceptable hourly average concentration of CO per cubic meter m³ of contaminated air established in the "National Ambient Air Quality Objectives". The volume of these 35 mg of gas will change according to the atmospheric conditions in which they are.

So, according to the law of ideal gases,

PV = nRT

where P, V, n and T are the pressure, volume, moles and temperature of the gas in question while R is the constant gas (0.082057 atm L / mol K)

The moles of CO will be,

n = 35 mg x $\frac{1 g}{1000 mg}$ x $\frac{1 mol}{28.01 g}$

→ n = 0.00125 mol

We clear V from the equation and substitute P = 0.92 atm and

T = -30 ° C + 273.15 K = 243.15 K

V = $\frac{0.00125 mol x 0.082057 \frac{atm L}{mol K} x 243 K}{0.92 atm}$

→ V = 0.0271 L

As 1000 cm³ = 1 L then,

V = 0.0271 L x $\frac{1000 cm^{3} }{1 L}$ = 27.09 cm³

Then the acceptable concentration c of CO in ppm is,

c = 27 cm³ / m³ = 27 ppm

To express this concentration in percent by volume we must consider that 1 000 000 cm³ = 1 m³ to convert 27.09 cm³ in m³ and multiply the result by 100%:

c = 27.09 $\frac{cm^{3} }{m^{3} }$ x $\frac{1 m^{3} }{1 000 000 cm^{3} }$ x 100%

c = 0.003 %

So, the acceptable concentration of CO if the temperature is -30 °C and pressure is 0.92 atm in ppm and as a percent by volume is 27.09 ppm and 0.003 %.

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Kamila [148]

Answer:

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