A pure substance __________ . must be an element. can be separated into simpler substances by physical means. has different chemical and physical properties depending on its source. can be separated into simpler substances by chemical means.

The molality of chloride ions is 4.63kg/L

Data;

Mole Fraction of MgCl2 = 0.04

The sum of mole fraction = 1

Mole fraction of water = 1 - 0.04 = 0.96

since the total number of moles = 1

Number of moles of MgCl2 = mole fraction * total number of moles

Number of moles of MgCl2

[tex]0.04 * 1 = 0.04 moles[/tex]

Number of moles of water =

[tex]0.96 * 1 = 0.96 moles[/tex]

1 moles of MgCl2 = 2 moles of Chloride ions

Number of moles of chloride ions

[tex]2 * 0.04 = 0.08 moles[/tex]

Number of moles of water = 0.96moles

mass of water = molecular weight * number of moles

mass of water =

[tex]18 * 0.96 = 17.28g[/tex]

let's convert this to kilogram

[tex]1000g = 1kg\\17.28g = x\\x = 0.01728kg\\[/tex]

The molality of the ions in the solution is

[tex]M = \frac{mass of solute}{volume of solution} \\M = \frac{0.08}{0.01728} =4.63 kg/L[/tex]

The molality of chloride ions is 4.63kg/L

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Answer:

Respiratory System

Explanation:

It connects with the lungs. The oxygen enters the body through the capillaries which are a part of the respiratory system.

Answer:

In this case the gravitational force is conservative, but the force you exert is not. So, as you lift the box, the work done by non-conservative forces (you) is not zero, and as a result, the total energy of the box increases.

But, Lifting a box is not scientifically considered "work"

Explanation: You do no work against gravity because you are not moving any distance (more accurately displacement) in the direction of the force i.e. the force and displacement are perpendicular once you have lifted the boxes. As work done = force x displacement parallel to the force, no work is done.

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The theory of phlogiston was the first to explain combustion process. J.J Becher was proposed this theory and states the existence of phlogisticated substances contain phlogiston and that they dephlogisticate when burned.

Combustion is the reaction of gases with atmospheric oxygen producing carbon dioxide and water. Gases like hydrocarbons easily undergoes combustion reaction.

Combustion is an exothermic reaction. Thus, heat is evolved to the surrounding. The conservation of mass is not only for combustion but it is the theory of every reaction.

The phlogiston idea, a debunked scientific hypothesis, suggested that combustible bodies contained a fire-like substance called phlogiston, which was produced after combustion.

Johann Joachim Becher originally put out the concept in 1667, and Georg Ernst Stahl later formalized it. The Phlogiston theory sought to explain a variety of chemical reactions, including burning and rusting Hence, option C is correct.

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Answer:

Biological Evidence

Explanation:

Both blood and sweat are fluids within the body, therefore, both are biological substances.

Answer:

First of all take separatory funnel.

Add the mixture of compounds into it.

Pour Water into it.

Add NaOH base. This will result in following reaction.

           CH₃CH₂CH₂COOH + NaOH  → CH₃CH₂CH₂COONa + H₂O

The resulting salt (CH₃CH₂CH₂COONa) is is soluble in water.

The water is the bottom layer (more density) and contains sodium butyrate.

Pour out the water from separatory funnel.

The organic layer (hexane) is left behind.

Now, take the aquous layer and neutralize it using HCl.

Once, neutralized remove the water.

The amount remaining after 36 years is 5 g

n = t / t½

n = 36 / 12

n = 3

N = N₀ / 2ⁿ

N = 40 / 2³

N = 40 / 8

N = 5 g

Therefore, the amount remaining after 36 years is 5 g

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The mass number for an atom of barium containing 56 protons and 82 neutrons is calculated by adding the number of protons and the number of neutrons which is 138.

In this case, the atomic number of barium is 56, which means it has 56 protons. The number of neutrons is given as 82.

To find the mass number, simply add the number of protons and the number of neutrons together:

Mass number = Protons + Neutrons

Mass number = 56 + 82

Mass number = 138

Therefore, the mass number for an atom of barium containing 56 protons and 82 neutrons is 138.

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Answer:

: B, if it is produced in an earlier step. Which term refers to a substance that is formed in one step of a reaction mechanism and consumed in a subsequent step of the reaction mechanism? D: reaction intermediate

Explanation:

pa brainlyes po kailangan lang talaga

Answer:

its D

Explanation:

trust

Answer:

Please see below

Explanation:

Organic acid - An organic acid is an organic compound with acidic properties. Organic acids should include amino acids, fatty acids, ketoacids, and a variety of other endogenous and exogenous acids.

Dilute acid - A dillute acid is an acid which has water in a ratio of 90:10 90 water and 10 acid.

Indicator -  a substance (as a dye) used to show visually (as by a change in color) the condition of a solution with respect to the presence of a particular material

Neutralization - the reaction of an acid and a base forming a salt and water.

Acid rain - rainfall made so acidic by atmospheric pollution that it causes environmental harm, chiefly to forests and lakes. The main cause is the industrial burning of coal and other fossil fuels, the waste gases from which contain sulphur and nitrogen oxides which combine with atmospheric water to form acids.

Answer:

E.)3p,4s,4d

Explanation:

In order as: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p… 1s will be filled first, with the maximum of 2 electrons. 2s will be filled next, with the maximum of 2 electrons. 2p will be filled next, with the maximum of 6 electrons.

B) 3p, 4s, 3d

hope this helped

Answer:

When two or more atoms are chemically joined together, this is called a molecule. In some cases, such as hydrogen and oxygen, the molecule is made entirely of the same atom, such as hydrogen gas (a molecule) is made entirely of two hydrogen atoms. Here, converting molecules to atoms is as simple as dividing by two.

Atoms can join together - they form bonds together - to make MOLECULES. For example, two atoms of hydrogen hook together to form a molecule of hydrogen

Answer:

Around 1260 hours

Answer:

1260 hours

Explanation:

Depending on your location, different states have different school hours and holidays. However, lets just assume it's the average. The average high school has 180 days of school each year with 7 hour school days.

180(7) = 1260 hours

Of course, this does not account for time spent at home studying, doing homework, tutoring, or other things of the sort.

Molarity

[tex]\\ \tt\hookrightarrow \dfrac{1.3}{0.42}=3.09M[/tex]

Now

[tex]\\ \tt\hookrightarrow \Delta T=K_f\times m\times i[/tex]

[tex]\\ \tt\hookrightarrow \Delta T=1.86(3.09)(2)=11.5°C[/tex]

Gregor Mendel researched and described the results of genetic crosses. He is considered the father of genetics.

Gregor Mendel was a botanist who made different genetic crosses using pea plants as a model organism.

Gregor Mendel observed as phenotypic traits were transmitted to the pea descendence in the F1 and F2 generation.

Gregor Mendel developed fundamental laws in genetics such as independent assortment and segregation.

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Answer: They are referred to as isotopes, which are a form of an element that has different numbers of neutrons in their nucleus.

Answer:

2 C2H2 + 5 O ---> 4 CO2 + 2 H2O

Explanation:

combustion reactions always end with CO2 + H2O

and you can use this website to balance out equations when you're stuck

https://en.intl.chemicalaid.com/tools/equationbalancer.php?equation=C2H2+%2B+O2+%3D+CO2+%2B+H2O

The pressure of the gas that has 3.00mol sample of CO2(g) is in a rigid 6.00L container at 400°C is 27.6atm.

The pressure of a gas can be calculated using the ideal gas law equation as follows:

PV = nRT

Where;

P × 6 = 3 × 0.0821 × 673

6P = 165.76

P = 165.76 ÷ 6

P = 27.6atm

Therefore, the pressure of the gas that has 3.00mol sample of CO2(g) is in a rigid 6.00L container at 400°C is 27.6atm.

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Answer:

I believe your answer is D. The use of light that has a lower frequency.

Hope this helped!

It is likely that Donna's blood alcohol concentration (BAC) will be about

10% higher than Allen's.

This is defined as the abundance of a constituent divided by the total

volume of a mixture.

During drinking, the concentration of alcohol is dependent on a lot of

factors such as the internal constituent of the body which is why Donna

will most likely have  a higher alcohol concentration.

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Answer:

Chemistry is essential for meeting our basic needs of food, clothing, shelter, health, energy, and clean air, water, and soil. Chemical technologies enrich our quality of life in numerous ways by providing new solutions to problems in health, materials, and energy usage

Answer:

▪Why Is chemistry important in industry?

[Chemistry helps our industry produce more materials—such as paints, plastics, iron or steel, cement, kerosene, and also motor oil. Chemistry also helps farmers to enrich the soil with chemicals ... to grow fresh vegetables.] Chemistry is important, especially in household things like condoms, cleaning, and cooking.

▪10 Reasons Why Chemistry Is Important

➢Chemistry helps explain everything.

➢Being interested in chemistry opens up career options.

➢Chemistry helps people develop strong analytical skills.

➢Understanding chemistry keeps people safe.

➢Chemistry helps protect the environment.

➢Chemistry is used in law.

➢Chemistry is used in the food industry

➢Chemistry is important in agriculture

➢Chemistry is used in medicine

➢Chemistry is important for space travel

[tex]TextFromYourMrEx...[/tex]

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Answer:

True. Heating may convert some matter into another substance, but the Law of Conservation of Mass states that matter may not be destroyed.

Explanation:

the answer is C

Answer:

is it 500 g

Explanation:

cause m stands for mass

To find the amount of heat produced, the value of m which we plug is 500 grams.

Amount of heat absorbed or released during any chemical change will be calculated as:

Q = mc∆T, where

Q = absorbed or released heat

m = mass of substance

c = specific heat of substance

∆T = change in temperature

So, according to question to calculate energy in place of m we will put the given mass of aluminum which is equal to 500g.

Hence required value of m is 500g.

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Answer: peptide

The type of bond that links the amino group of one amino acid to the acid group of another is a(n) peptide bond.

Answer:

Chemical weathering occurs when water dissolves minerals in a rock, producing new compounds. ... Hydrolysis occurs, for example, when water comes in contact with granite. Feldspar crystals inside the granite react chemically, forming clay minerals. The clay weakens the rock, making it more likely to break.

Carbonation-As rain goes through the air and into the ground, it grabs carbon dioxide, creating carbonic acid. This weak acid reacts with the calcium carbonate in stones when it seeps into the cracks.

Oxidation- Rust forms when the iron or steel in your car reacts with the oxygen in the air to form iron oxide. The resulting red substance can be quite brittle, so much so that you could literally poke a hole in it with your finger. Rocks with iron can go through the same process, too.

Hydration- Hydration is a type of chemical weathering where water reacts chemically with the rock, modifying its chemical structure.

Acidification-Acid rain is water with sulfuric and nitric acids from the burning of coal and fossil fuels, along with volcano eruptions. The acids create a reaction when they hit the stone, causing the surface to wear and the composition to soften. Acidification can also be caused by organisms like lichens, which are created from algae and fungi.

Answer:

500

Explanation:

from the average and if yoy multiple and then add your % and x you would get 500 to 600

Answer:

b

Explanation:

use Avogadro's number to convert molecules to moles

1 mole is equal to 6.023 × 10 ²³ molecules. 7.56 moles of carbon dioxide (CO2) are equivalent to 4.55 X 10^24 molecules.

The term mole is defined as the amount of substance of a system which contains as many elementary entities.

One mole of any substance is equal to 6.023 × 10²³ units of that substance such as atoms, molecules, or ions. The number 6.023 × 10²³ is called as Avogadro's number or Avogadro's constant.

The mole concept can be used to convert between mass and number of particles.

1 mole of any substance = 6.023 × 10²³molecules

1 mole of carbon dioxide = 6.023 × 10²³molecules

Then  4.55 X 10^24 molecules of CO₂ =  4.55 X 10^24 × 1 mole / 6.023 × 10²³

= 7.56 moles

Thus, 7.56 moles of carbon dioxide (CO2) are equivalent to 4.55 X 10^24 molecules.

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Explanation:

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