CHEMISTRY HIGH SCHOOL

Which sample of matter is a mixture?
(1) Br2(ℓ) (3) KBr(s)
(2) K(s) (4) KBr(aq)

Answers

Answer 1

Answer:

Answer:

KBr (aq) is a mixture.

Explanation:

Mixture is defined as the combination of two non reacting species. Let's discuss each option one by one.

a) Br₂(l):

This Bromine is not a mixture because the bracket specifying the state of Br₂ is liquid. Hence, as bromine is a liquid at room temperature, so this compound is purely Br₂.

b) KBr (s):

KBr is also present in pure form because in bracket solid is written.

c) K (s):

Potassium is also present in pure form as the bracket is specifying solid, as KBr is solid at room temperature.

d) KBr (aq):

This is a mixture of KBr and water. Because KBr being an electrolyte when dissolved in water it is hydrated as follow,

KBr (s) -----water------> K⁺ (aq) + Br⁻ (aq)

Answer 2

Answer:

$\boxed{\left( {\text{4}} \right){\text{ KBr}}\left( {aq} \right)}$ is a mixture.

Further explanation:

Mixture:

It is formed by the physical combination of two or more different substances. Mixtures do not have any fixed formula and their composition is also variable. There is retention in the properties of constituents even after the formation of mixtures.

(1) ${\text{B}}{{\text{r}}_2}\left( l \right)$

Bromine is present in liquid in its pure state. The “l” written in the parenthesis after denotes its physical state which is the same as that of its pure form. So it is not a mixture.

(2) K (s)

Potassium is present in solid in its pure form. The “s” written in the parenthesis after K describes its physical state which is the same as that of its pure form. So it is not a mixture.

(3) KBr (s)

It is an ionic salt which is solid in nature. The “s” written in the parenthesis after KBr denotes its physical state which is the same as that of its pure form. So it is not a mixture.

(4) KBr (aq)

The “aq” written in the parenthesis after KBr indicates that it is present in the aqueous phase. This means it is formed by the combination of KBr and water so it is a mixture.

Learn more:

The major contribution of Antoine Lavoisier to chemistry: brainly.com/question/2500879
Example of physical change: brainly.com/question/1119909

Answer details:

Grade: High School

Chapter: Elements, compounds, and mixtures

Subject: Chemistry

Keywords: mixture, physical combination, substances, fixed formula, variable, composition, retention, properties, Br2, K, KBr.

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The valence of aluminum is +3, and the valence of chlorine is –1. The formula for aluminum chloride iscorrectly written as
A. ClAl3.
B. Cl3Al.
C. AlCl3.
D. Al3Cl.

Answers

The correct option is C.i.e. AlCl3Given:The valence of aluminum is +3, and the valence of chlorine is –1. Thus, 3 chlorine atoms each of (-1 charge )combine to make the charge balance because of Al (3+). Thus, 1 atom of Aluminum (Al) binds with three atoms of Chlorine (Cl).Thus, the net foromula becomes AlCl3

AICI3

which is choice c.

Aluminium chloride

Chemical compound

DescriptionAluminium chloride is the main compound of aluminium and chlorine. It is white, but samples are often contaminated with iron(III) chloride, giving it a yellow color. The solid has a low melting and boiling point. Wikipedia

IUPAC ID: aluminium chloride

Molar mass: 133.34 g/mol

Soluble in: Water

Related Lewis acids: Iron(III) chloride; Boron trifluoride

Heat capacity (C): 91.1 J/mol·K

Other names: aluminium(III) chloride; aluminum trichloride

Consider the reaction: 2 H2O (g)-->2 H2 (g) + O2 (g). ΔH=483.6 Kj/mol. If 2 moles of H2O (g) are converted H2(g) and O2(g) against a pressure of 1 atm at 125 degrees Celcius what is ΔE of reaction?

Answers

Answer : The value of $\Delta E$ of the reaction is, 480.29 KJ.

Explanation :

Formula used :

$\Delta E=\Delta H-\Delta n_g* RT$

where,

$\Delta E$ = internal energy of the reaction = ?

$\Delta H$ = enthalpy of the reaction = 483.6 KJ/mole = 483600 J

$\Delta n_g$ = change in the moles of the reaction = Moles of product - Moles of reactant = 3 - 2 = 1 mole

R = gas constant = 8.314 J/mole.K

T = temperature = $125^oC=273+125=398K$

Now put all the given values in the above formula, we get:

$\Delta E=483600J-(1mole* 8.314J/mole.K* 398K)$

$\Delta E=480291.028J$

$\Delta E=480.29KJ$

Therefore, the value of $\Delta E$ of the reaction is, 480.29 KJ.

dE = dH - PdV

2 H2O(g) → 2 H2(g) + O2(g)

You can see that there are 2 moles of gas in the reactants and 3 moles of gas in the products.

1 moles of ideal gas occupies the same volume as 1 mole of any other ideal gas under the same conditions of temp and pressure.

Since it is done under constant temp and pressure that means the volume change will be equal to the volume of 1 mole of gas

2 moles reacts to form 3 moles

The gas equation is

PV = nRT
P = pressure
V = volume (unknown)
n = moles (1)
R = gas constant = 8.314 J K^-1 mol^-1
- the gas constant is different for different units of temp and pressure (see wikki link) in this case temp and pressure are constant, and we want to put the result in an equation that has Joules in it, so we select 8.314 JK^-1mol^-1)
T = temp in Kelvin (kelvin = deg C + 273.15
So T = 403.15 K

Now, you can see that PV is on one side of the equation, and we are looking to put PdV in our dE equation. So we can say

dE = dH -dnRT (because PV = nRT)

Also, since the gas constant is in the unit of Joules, we need to convert dH to Joules

dH = 483.6 kJ/mol = 483600 Joules/mol

dE = 483600 J/mol - (1.0 mol x 8.314 J mol^-1K-1 x 403.15 K)
dE = 483600 J/mol - 3351.77 J
dE = 480248.23 J/mol
dE = 480.2 kJ/mol

The term biodiversity means the variety of organism (true or false)

Answers

Answer:

true

Explanation:

What is the average kinetic energy of 1 mole of a gas that is at 100 degrees Celsius?

Answers

To simplify our solutions, we have to assume that the gas we are referring is ideal. The kinetic energy of of ideal gas is a funtion of moles and temperature only.
KE = (3/2)(nRT)
= (3/2)(1mol)(8.314J/molK)(100+273.15) = 4204.6J

Although incineration can break down harmful chemicals, the byproduct is hazardous.a. True
b. False

Answers

Answer: The given statement is true.

Explanation:

Incineration: It is a technique in which organic substance present in waste material is burned down to break them into its components.

For: Example : Burning of powder of wooden chips gives carbon dioxide gas ,nitrogen-dioxide in small amounts and heat energy.

Although incineration can break down harmful chemicals but the by-product formed are hazardous because:

Oxides of nitrogen and sulfurs are also released which pollutes the air and becomes the main cause for acid rains.
Green house gases are produced which disturbs the balance of atmosphere and climate.
Increases air pollution by which it becomes unfit to breathe in.
Also pollutes soil.

Hence, the given statement is true.

A, true is the answer and cluke u help me please

Which is a characteristic of mixtures? They are chemically bonded together. They can be classified as pure substances. They have fixed ratios between their components. They can be separated by physical processes.

Answers

the answer is d i just took the quiz

The statement "They can be separated by physical processes" is a characteristic of mixtures (option D)

What are mixtures?

Mixtures are physical combinations of two or more substances. The components of a mixture are not chemically bonded together, and they can be separated by physical processes such as filtration, distillation, and evaporation.

Pure substances, on the other hand, are made up of only one type of atom or molecule. They cannot be separated by physical processes.

Therefore, the correct answer is They can be separated by physical processes (option D)

Learn about mixtures here brainly.com/question/2331419

#SPJ6

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