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3 years ago

I need help please i need it today

Chemistry

1 answer:

creativ13 [48]3 years ago

8 0

Answer:

what help.....

i don't understand your question what help....

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Determine the concentration of sulfuric acid that needed 47 mL of 0.39M potassium hydroxide solution to neutralize a 25 mL sampl

77julia77 [94]

Answer:

0.37M

Explanation:

Since sulfuric acid, H₂SO₄, is a diprotic acid and potassum hydroxide, KOH, contains one OH⁻ in the formula, the number of moles of potassium hydroxide must be twice the number of moles of sulfuric acid.

1. Determine the number of moles of KOH in 47mL of 0.39M potassium hydroxide solution

number of moles = molarity × volume in liters

number of moles = 0.39M × 47mL × 1liter/1,000 mL = 0.1833mol

2. Determine the number of moles of sulfuric acid needed

number of moles of H₂SO₄ = number of moles of KOH/2 = 0.1833/2 = 0.009165mol

3. Determine the concentration that contains 0.009165 mol in 25mL of the acid.

Molarity = number of moles / volume in liters

M = 0.009165mol/(25mL) × (1,000mL/liter) = 0.3666M

Round to two significant figures: 0.37M

7 0

3 years ago

Which of the following molecules is polar?

alexandr1967 [171]

Answer

CH3Cl is polar amoungst the choices

5 0

3 years ago

In the reaction 4AI+_O2 2AI2O3, what coefficient should be placed in front of the O2 to balance the reaction?

Olegator [25]

Answer: 3

Explanation: I took the k12 quiz

3 0

3 years ago

Does SiF4 have polar covalent bonds?

Kamila [148]

Answer:

SiF4 is not a polar covalent bond.

Explanation:

SiF4 is a nonpolar molecule because the fluorine's are arranged around the central silicon atom in a tetrahedral molecule with all of the regions of negative charge cancelling each other out.

8 0

3 years ago

Which aqueous solution has the highest boiling point at standard pressure?(1) 1.0 M KC1(aq) (3) 2.0 M KCl(aq)(2) 1.0 M CaC12(aq)

miss Akunina [59]

Answer:

(4) 2.0 M CaCl₂(aq).

Explanation:

Adding solute to water elevates the boiling point.

The elevation in boiling point (ΔTb) can be calculated using the relation:

ΔTb = i.Kb.m,

where, ΔTb is the elevation in boiling point.

i is the van 't Hoff factor.

van 't Hoff factor is the ratio between the actual concentration of particles produced when the substance is dissolved and the concentration of a substance as calculated from its mass. For most non-electrolytes dissolved in water, the van 't Hoff factor is essentially 1.

Kb is the molal elevation constant of water.

m is the molality of the solution.

(1) 1.0 M KCl(aq):

i for KCl = no. of particles produced when the substance is dissolved/no. of original particle = 2/1 = 2.

suppose molarity = molality, m = 1.0 m,

∴ ΔTb for (1.0 M KCl) = i.Kb.m = (2)(Kb)(1.0 m) = 2(Kb).

(2) 2.0 M KCl(aq):

i for KCl = no. of particles produced when the substance is dissolved/no. of original particle = 2/1 = 2.

suppose molarity = molality, m = 2.0 m,

∴ ΔTb for (1.0 M KCl) = i.Kb.m = (2)(Kb)(2.0 m) = 4(Kb).

(3) 1.0 M CaCl₂(aq):

i for CaCl₂ = no. of particles produced when the substance is dissolved/no. of original particle = 3/1 = 3.

suppose molarity = molality, m = 1.0 m,

∴ ΔTb for (1.0 M KCl) = i.Kb.m = (3)(Kb)(1.0 m) = 3(Kb).

(4) 2.0 M CaCl₂(aq):

i for CaCl₂ = no. of particles produced when the substance is dissolved/no. of original particle = 3/1 = 3.

suppose molarity = molality, m = 2.0 m,

∴ ΔTb for (1.0 M KCl) = i.Kb.m = (3)(Kb)(2.0 m) = 6(Kb).

So, the aqueous solution has the highest boiling point at standard pressure is: (4) 2.0 M CaCl₂(aq).

6 0

3 years ago