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4 years ago

Will make brainliest if answer correctly.

Chemistry

1 answer:

Sonja [21]4 years ago

6 0

Answer:

They are in same group/family.

Explanation:

Alkaline earth metals are present in group 2 of periodic table. There are six elements in second group. Beryllium, magnesium, calcium, strontium, barium and radium.

All have two valance electrons but in different energy levels. Thus they have similar chemical properties.

Electronic configuration of calcium.

Ca = [Ar] 4s²

Electronic configuration of strontium.

Sr = [Kr] 5s²

They are present in group two and have same number of valance electrons (two valance electrons) and show oxidation state +2 by loosing two valance electrons. They also show similar reactivity.

They react with oxygen and form oxide.

2Sr + O₂ → 2SrO

2Ca + O₂ → 2CaO

this oxide form hydroxide when react with water,

SrO + H₂O → Sr(OH)₂

CaO + H₂O → Ca(OH)₂

With sulfur,

Sr + S → SrS

Ca + S → CaS

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Calculate the percent yield of benzyl alcohol Sue obtained when doing the following reaction. Sue started with 2.1 g of benzoic

Pachacha [2.7K]

Answer:

The percent yield is 116.6 %

Explanation:

Step 1: Data given

Mass of benzoic anhydride = 2.1 grams

Mass of sodium borohydride = 0.15 grams

Molar mass of benzoic anhydride = 226.23 g/mol

Molar mass of NaBH4 = 37.83 g/mol

Mass of benzyl alcohol produced = 0.5 grams

Step 2: The balanced equation

C14H10O3 + NaBH4 → C7H6O2 + C7H8O + NaB

Step 3: Calculate moles of C14H10O3

Moles C14H10O3 = Mass / molar mass

Moles C14H10O3 = 2.10 grams / 226.23 g/mol

Moles C14H10O3 = 0.00928 moles

Step 4: Calculate moles NaBH4

Moles NaBH4 = 0.150 grams / 37.83 g/mol

Moles NaBH4 = 0.00397 moles

Step 5: Calculate limiting reactant

For 1 mol of C14H10O3 we need 1 mol of NaBH4 to produce 1 mol of C7H8O

NaBH4 is the limiting reactant. It will completely be consumed ( 0.00397 moles).

C14H10O3 is in excess. There will react 0.00397 moles.

There will remain 0.00928 - 0.00397 = 0.00531 moles

Step 6: Calculate moles of C7H8O

For 1 mol of C14H10O3 we need 1 mol of NaBH4 to produce 1 mol of C7H8O

For 0.00397 of C14H10O3 we need 0.00397 mol of NaBH4 to produce 0.00397 mol of C7H8O

Step 7: Calculate mass of C7H8O

Mass of C7H8O = Moles * molar mass

Mass of C7H8O = 0.00397 moles * 108.14 g/mol

Mass of C7H8O = 0.429 grams = theoretical yield

Step 8: Calculate % yield

% yield = (actual yield/ theoretical yield) * 100%

% yield = 0.5/0.429) *100 %

% yield = 116.6 %

The percent yield is 116.6 %

3 0

4 years ago

Why ice floats on water is a physical change

creativ13 [48]

Answer:

Ice floats on water because it is less dense than water. When water freezes into its solid form, its molecules are able to form more stable hydrogen bonds locking them into positions. Because the molecules are not moving, they're not able to form as many hydrogen bonds with other water molecules. Ice is a unique substance because it is solid-state — ice — is less dense than its liquid state. Because of this property, ice floats in water. Physical properties are characteristics of a substance. They do not change. Ice floats on water because it is less dense than water. When water freezes into its solid form, its molecules are able to form more stable hydrogen bonds locking them into positions.

5 0

4 years ago

what is the molar mass of nicotine (C10H14N2)? Question 6 options: 14.11 g/mol 28.02 g/mol C 120.1 g/mol 162.2 g/mol C

viva [34]

Answer:

162.2 g/mol

Explanation:

Molar mass is defined as the mass in 1 mole of the substance. It is calculated by adding the molar mass of the substituents each multiplied by the subscript they have in the formula.

Thus, To calculate molar mass of nicotine having formula, $C_{10}H_{14}N_2$

Molar mass of C = 12.0107 g/mol

Molar mass of H = 1.00784 g/mol

Molar mass of N = 14.0067 g/mol

Thus, molar mass of nicotine = $12.0107\times 10+1.00784\times 14+14.0067\times 2$ = 162.2 g/mol

6 0

4 years ago

Using this balanced equation: 2 NaOH + H2SO4 —> H2O + Na2SO4

mars1129 [50]

<h3>Answer:</h3>

266.325 g

<h3>Explanation:</h3>

We are given the balanced equation;

2NaOH + H₂SO₄ → H₂O + Na₂SO₄

Mass of NaOH as 150 g

We are required to determine the mass of Na₂SO₄ that will be formed.

<h3>Step 1: Determine the number of moles of NaOH</h3>

Moles = Mass ÷ molar mass

Molar mass of NaOH is 40.0 g/mol

Therefore;

Moles of NaOH = 150 g ÷ 40 g/mol

= 3.75 moles

<h3>Step 2: Determine the number of moles of sodium sulfate formed</h3>

From the equation 2 moles of NaOH reacts with sulfuric acid to form 1 mole of sodium sulfate.
Therefore; mole ratio of NaOH : Na₂SO₄ is 2 : 1

Thus, moles of Na₂SO₄ = Moles of NaOH ÷ 2

= 3.75 moles ÷ 2

= 1.875 moles

<h3>Step 3: Determine the mass of Na₂SO₄ produced.</h3>

we know that;

Mass = Moles × Molar mass

Molar mass of Na₂SO₄ is 142.04 g/mol

Therefore;

Mass of Na₂SO₄ = 1.875 moles × 142.04 g/mol

= 266.325 g

Thus, the mass of sodium sulfate formed 266.325 g

7 0

3 years ago

Isoniazid is used in the treatment of tuberculosis and multiple sclerosis. Identify each lone pair as either localized or deloca

dolphi86 [110]

Answer:

Please find the complete question and its solution in the attached file:

Explanation:

4 0

3 years ago