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3 years ago

Two question please help

Chemistry

1 answer:

Anton [14]3 years ago

4 0

Answer:

a) A. Alkaline earth metals

b) C. 2,8

Explanation:

a) The oxidation state (or the charge) of various elements in a group can be deduced based on the valence electron configuration.

The general valence electron configuration is as follows:

Alkali metals : ns¹

Alkaline earth metals: ns²

Noble gases: ns²np⁶

Halogens: ns²np⁵

Therefore the alkaline earth metals have 2 electrons in their valence shell which can be lost resulting in a +2 oxidation state.

b) The principal quantum number 'n' represents the distance of a particular shell from the nucleus.

n = 1,2,3..

The angular momentum quantum number 'l' represents the type or shape of the orbital

l = 0,1,2...(n-1)

l = 0 corresponds to 's' orbital which can hold a maximum of 2 electrons

l = 1, 'p' orbital which can hold a maximum of 6 electrons

l = 2, 'd' orbital which can hold a maximum of 10 electrons

Therefore:

The first energy shell will have n = 1 and l = 0

i.e. the s-orbital with 2 electrons

The second energy shell will have n = 2, and l = 0,1

i.e one s orbital with 2 electrons

one p-orbital with 6 electrons. Total = 2+6 = 8 electrons.

The first energy shell around a nucleus can hold _____2__ electrons. The second energy shell can hold ____8____.

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How many moles of oxygen gas react to yield 0.200 mole water? . . C5H12(g) + 8 O2(g) = 5 CO2(g) + 6H2O(g)

Harlamova29_29 [7]

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4 years ago

When 25.0 g of ch4 reacts completely with excess chlorine yielding 45.0 g of ch3cl, what is the percentage yield, according to c

snow_tiger [21]

Percentage yield = (actual yield / theoretical yield) x 100%

The balanced equation for the reaction is,
CH₄(g) + Cl₂(g) → CH₃Cl(g) + HCl(g)

Since there is excess of Cl₂ gas, we can assume that all of CH₄ gas are reacted.

Moles of CH₄(g) = mass / molar mass
= 25.0 g / 16 g/mol
= 1.5625 mol

The stoichiometric ratio between CH₄(g) and CH₃Cl(g) is 1 : 1

Hence moles of CH₃Cl(g) = 1.5625 mol

Molar mass of CH₃Cl(g) = 50.5 g/mol

Mass of CH₃Cl(g) = number of moles x molar mass
= 1.5625 mol x 50.5 g/mol
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Hence theoretical yield = 78.9 g
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Hence,
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3 years ago

Aqueous potassium phosphate was mixed with aqueous magnesium chloride, and a crystallized magnesium phosphate product was formed

scoray [572]

Answer: The other product formed is potassium chloride.

Explanation:

Precipitation reaction is defined as the chemical reaction in which an insoluble salt is formed when two solutions are mixed containing soluble substances. The insoluble salt settles down at the bottom of the reaction mixture.

The chemical equation for the reaction of potassium phosphate and magnesium chloride follows:

$2K_3PO_4(aq.)+3MgCl_2(aq.)\rightarrow Mg_3(PO_4)_2(s)+6KCl(aq.)$

By Stoichiometry of the reaction:

2 moles of aqueous solution of potassium phosphate reacts with 3 moles of aqueous solution of magnesium chloride to produce 1 mole of solid magnesium phosphate and 6 moles of aqueous solution of potassium chloride.

Hence, the other product formed is potassium chloride.

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4 years ago