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3 years ago

Naturally occurring chlorine that is put in pools is 75.53 percent 35Cl and 24.47 percent Cl. Calculate the average atomic mass.

Chemistry

1 answer:

LenKa [72]3 years ago

5 0

A_r = 35.5

The average atomic mass of Cl is the weighted average of the atomic masses of its isotopes.

We multiply the atomic mass of each isotope by a number representing its relative importance (i.e., its % abundance).

Thus,

0.7553 × 35 u = 26.4 u

0.2447 × 37 u = 9.05 u

TOTAL = 35.5 u

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What are two ways condensation differs from boiling?

NARA [144]

Condensation is when vapor liquidizes and gathers on top of a surface, while boiling is turning a liquid into a gas or vapor. They are opposites. In the first, the molecules of the substance split and separate and increase the volume, while in the second they come together and reduce the volume.

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3 years ago

Two solutions, initially at 24.60 °C, are mixed in a coffee cup calorimeter (Ccal = 15.5 J/°C). When a 100.0 mL volume of 0.100

yulyashka [42]

Answer:

ΔH = -59.6kJ/mol

Explanation:

The reaction that occurs between Ag⁺ and Cl⁻ ions is:

Ag⁺ + Cl⁻ → AgCl(s) + ΔH

To find ΔH we need to obtain moles of reaction and heat released in the reaction because ΔH is defined as heat released per mole of reaction.

Moles of reaction:

Moles of Ag⁺ and Cl⁻ added are:

Ag⁺: 0.100L * (0.100mol / L) = 0.01moles

Cl⁻: 0.100L * (0.200mol / L) 0 0.02 moles

That means limiting reactant is Ag⁺ and moles of reaction are 0.01 moles

Heat released:

To find heat released we must use coffe cup calorimeter equation:

Q = C*m*ΔT

Where C is specific heat of solution (4.18J/g°C), m is the mass of solution (200g because there are 100 + 100mL = 200mL and density of solution is 1g/mL) and ΔT is change in temperature (25.30°C - 24.60°C = 0.70°C).

Replacing:

Q = C*m*ΔT

Q = 4.18J/g°C * 200g * 0.70°C

Q = 585,2J

Is total heat released.

The calorimeter absorbs:

15.5J / °C * 0.7°C = 10.85

Thus, when 0.01 moles reacts, 585.2J + 10.85 = 596.05J are released (Heat released is heat abosrbed by calorimeter + Heat absorbed by water) and ΔH is:

ΔH = 596.05J / 0.01 moles =

ΔH = 59605J / mol =

As heat is released, ΔH < 0.

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4 years ago

Both kepler's laws and newton's laws tell us something about the motion of the planets, but there are fundamental differences be

I am Lyosha [343]

Answer: See description

Explanation:

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1. planets orbit the sun in elliptical paths

2. the orbial period is related to the orbital distance by $T^{2} = d^3$

where T is the orbital period and d is the orbital distance, T is in years and d is measured in units of the earth sun distance.

3. planets closer to the sun move faster than planets far away from it.

Newton:

Newton discovered that there is a consequence to the gravity exerted by objects: mass, the heavier the planet, the more gravitational force it posseses ( thats why we orbit the sun)

with the gravitational force $F_{gravitational} =G \frac{Mm}{r^2}$ newton discovered the inverse-quadratic relationship between the distance of the planets and the acceleration exerted by the force one could exert on another.

Kepler's laws were mostly based on observed evidence with quantitative relationships between the mentioned variables. Newton's laws are based on calculus and symbolic equations. While Kepler's mode is basic, Newton took another step in and build a more general model for gravity (which was improved by general relativity later). In a nutshell Newton proved the scientific causes for Kepler's laws...

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3 years ago

Complete the reaction by writing the formulas of the products. CH 3 COOH + NH 3 − ⇀ ↽ − CH_{3}COONH_{4}^{+} CH 3 COONH + 4 The K

cricket20 [7]

Answer:

Products are favored.

Explanation:

The acid-base reaction of CH₃COOH (acid) with NH₃ (base) produce:

CH₃COOH + NH₃ ⇄ CH₃COO⁻ + NH₄⁺ Kr = ?

It is possible to know Kr of the reaction by the sum of acidic dissociations of the half-reactions. That is:

CH₃COOH ⇄ CH₃COO⁻ + H⁺ Ka = 1.8x10⁻⁵

NH₃ + H⁺ ⇄ NH₄⁺ 1/Ka = 1/ 5.6x10⁻¹⁰ = 1.8x10⁹

___________________________________

CH₃COOH + NH₃ ⇄ CH₃COO⁻ + NH₄⁺ Kr = 1.8x10⁻⁵×1.8x10⁹ = 3.2x10⁴

As Kr is defined as:

Kr = [CH₃COO⁻] [NH₄⁺] / [CH₃COOH] [NH₃]

And Kr is > 1

[CH₃COO⁻] [NH₄⁺] > [CH₃COOH] [NH₃],

showing products are favored.

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3 years ago

An aqueous solution of glucose has molality of 6.81 and a density of 1.2 g/ml what is the molarity of glucose in the solution

andriy [413]

Answer:

the molarity is 3.68 moles/L

Explanation:

the molality of the solution of sucrose is

m= moles of glucose / Kg of solvent (water)= 6.81 ,

since the molecular weight of glucose is 180.156 gr/mole , then per each kilogram of solvent there is

6.81 moles*180.156 gr/mole + 1000 gr of water = 2226.86 gr of solution

from the density

volume of solution = mass of solution/density = 2286.86 gr / 1.2 gr/ml = 1855.71 ml

therefore there is 1000 gr of water in 1855.71 ml

then the molarity M is

M= moles of glucose / L of solution = (moles of glucose / Kg of solvent) * (Kg of solvent/L of solution) = 6.81 moles/Kg * 1Kg/1.85 L = 3.68 moles/L

M= 3.68 moles/L

Note:

- Would be wrong in this case to assume density of water = 1 Kg/L since the solution is heavily concentrated in glucose and therefore the density of water deviates from its pure value.

3 0

4 years ago