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a_sh-v [17]
3 years ago
8

How many valence electrons are in a stable ion of a period 4 metal?

Chemistry
1 answer:
marusya05 [52]3 years ago
8 0
What kind of metal is it
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Describe the scale used to measure the basicity of a substance. Demonstrate how you could differentiate a weak base from a stron
Verizon [17]

Answer:

Basicity is measured on a scale called the pH scale. On this scale, a pH value of 7 is neutral, and a pH value of more than 7 to 14 shows increasing basicity.

pH value of 7 is weak base and value of 14 means strong base.

8 0
3 years ago
Photosynthesis by land plants leads to the fixation each year of about 1 kg of carbon on the average for each square meter of an
Rama09 [41]

Answer:

a) mass of carbon directly above 1 ( each)  square meter of the earth is 1.65kg

b) all CO₂ will definitely be used up from the atmosphere directly above a forest in 1.65 years

Explanation:

first we calculate the moles of carbon

moles = mass/molar mass

= 1kg/12gmol⁻¹

= 1000g/12gmol⁻¹

= 83.33 mol

now using the ideal gas equation

we find the volume of co₂required based on 83.33 moles

PVco₂ = nRT

Vco₂ = nRT/P

Vco₂ = (83.22mol × 0.0821L atm k⁻¹ mol⁻¹ 298 K) / 1 atm

Vco₂ = 2083.73 L

so since CO₂ in air is 0.0390% by volume in the atmosphere, we find the the total amount of air required to obtain 1kg carbon

therefore

Vair × 0.0390/100 = 2038.73L

Vair = (2038.73L × 100) / 0.0390

Vair = 5.23 × 10⁶L

therefore 5.23 × 10⁶ L of air will be required to obtain 1kg carbon

a)

Here we calculate the mass of air over 1 square meter of surface.

Remember that atmospheric pressure is the consequence of the force exerted by all the air above the surface; 1 bar is equivalent to 1.020×10⁴kgm⁻²

NOW

mass of air = 1.020×10⁴kgm⁻² × 1m²

= 1.020×10⁴kg

= 1.020×10⁷g    [1kg = 10³g]

we now find the moles of air associated with it

moles = mass/molar mass

= 1.020 × 10⁷g / ( 20%×Mo₂ + 80%×Mn₂)

= 1.020 × 10⁷g / ( 20%×32gmol⁻¹ + 80%×28gmol⁻¹)

= 1.020 × 10⁷g / 28.8 gmol⁻¹

= 354166.67mol

so based on the question, for each mole (air), there is 0.0390% of CO₂

now to calculate the moles of CO₂ we say;

MolesCo₂ = 0.0390/100 × 354166.67mol

= 138.125 moles

Now we calculate mass of CO₂ from the above findings

Moles = mass/molar mass

mass = moles × molar mass

= 138.125 moles × 12gmol⁻¹

= 1657.5g

we covert to KG

= 1657.5g / 1000

mass = 1.65kg

therfore mass of carbon directly above 1 ( each)  square meter of the earth is 1.65kg

b)

to find the number years required to use up all the CO₂, WE SAY

Number of years = total carbon per m² of the forest / carbon used up per m² from the forest per year

Number of years = 1.65kgm⁻² / 1kg²year⁻¹

Number of years = 1.65 years

Therefore all CO₂ will definitely be used up from the atmosphere directly above a forest in 1.65 years

6 0
3 years ago
Wat are the five assumption of kinetic therory of gases​
il63 [147K]

Answer:

The five assumption of Kinetic molecular theory are given below.

Explanation:

Kinetic molecular theory of gasses stated that,

1) Gases consist of large number of smaller particles which are distance apart from each others.

2) The gas molecules collide with each other and also with wall of container and this collision is elastic.

3) Gas molecules are in continuous random motion and posses kinetic energy.

4) The forces of attraction between gas molecules are very small and considered negligible.

5) The temperature of gas is directly proportional to average kinetic energy of gas molecules.

6 0
2 years ago
What is the concentration of a 500 mL solution with 25 mol of HF? Write your answer with TWO decimal places and round accordingl
statuscvo [17]

Answer:

23

Explanation:

3 0
2 years ago
Where y and x are concentrations of the peptide in the extract and raffinate, respectively in g/L. It is desired to extract at l
zubka84 [21]

Answer:

sadjf akasj fk a

sadkf

ldj

a d i

i d o n t             k n o w

Explanation:

6 0
3 years ago
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