The boiling point of a substance is known to be 293°C. What is the vapor pressure of that substance at 220°C?

Answer:

elementos original

set onde

Answer:

2(CaSO4)*H2O

Explanation:

To solve this question we need to find the moles water, H2O, of calcium sulfate, CaSO4 as follows:

The molar mass of the anhydrous CaSO4 are 136.14g/mol and the molar mass of the hemihydrate is 145.15g/mol. The differences in molar mass represents the additional mass that water is producing:

145.15g/mol - 136.14g/mol = 9.01g/mol

A 1 mole of water weighs 18.015g/mol, the additional mass of water is due the addition of 1/2 moles of H2O. That means we have 1 mole of CaSO4 per 1/2 mole of H2O. That is the same:

2(CaSO4)*H2O

And this is the formula that gives the correct ratio for the hemihydrate.

Complete question is;

Which statements accurately describe the evidence that scientists gather using fossils? Check all that apply.

A) The fossil record can be used to date rocks.

B) Living things with many cells have always lived on Earth.

C) Simple organisms are found only in young rocks.

D) Geologists study ancient remains of plants and animals.

E) Scientists can figure out what ancient living things ate.

F) Pollen and seeds help provide clues about ancient climates.

Answer:

A) The fossil record can be used to date rocks

E) Scientists can figure out what ancient living things ate.

F) Pollen and seeds help provide clues about ancient climates

Explanation:

In scientific research, fossils are sometimes referred to as animals and plant. Now, in studying records of fossils, it will be easy to know the length of existence of living things on the Earth. Also, we can be able to identify the manner in which different relationships exists between plants and animals by predicting their lifestyles, location of their habitation e.t.c which can be used to predict the old time climates.

Looking at the options given in relation to the explanation given, options A, E & F are correct

Potassium reacts with dilute hydrochloric acid to give potassium chloride and hydrogen gas. Heating small pieces of Potassium in air results in the substance melting without any flame being seen and turning instantly into a mixture of potassium peroxide and potassium super oxide.

A Potassium Reaction involves a process in which Potassium is mixed with another substance which react to form something else. Reactions are manifested by the disappearance of properties characteristic of Potassium and the appearance of new properties in the new substance or Compound.

The substances initially involved in a reaction are called reactants or reagents. The most important of the Potassium compounds is Potassium chloride (KCl) which is used in the production of fertilizers and chemicals and also as a salt substitute. Other important compounds are Potassium nitrate (KNO3), also known as saltpeter which is used in the production of gunpowder, fertilizers and pyrotechnics and Potassium hydroxide (KOH) is used to make detergents and soaps. Reactions are described with Chemical Formula and Equations.

Answer:

D

Explanation:

The answer for the first question is definitely D. 10, as it is a neutral atom, therefore numbers of p+ and e- are the same.

Hope it helps you

According to the electronic configuration and capacity of shells there are 10 electrons that  would make the d shell complete.

Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.

Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.

Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.

Learn more about electronic configuration,here:

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Answer:

answer is d on edge

Explanation:

The name of the molecule shown is Ethanol.

Ethanol is a alcoholic substance that is formed from fermentation of glucose in the presence of yeast or microorganisms.

It has a chemical group that have methyl group, hydroxyl group OH which is bonded to carbon atom.

Therefore, The name of the molecule shown is Ethanol.

Learn more about ethanol below.

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Answer:

Explanation:

Answer:

"0.583" is the appropriate answer.

Explanation:

Let,

The initial constant of [tex]N_2O_4[/tex] be "C".

Amount of [tex]N_2O_4[/tex] dissociated into [tex]NO_2[/tex] be "x".

now,

                                     [tex]N_2O_4 \rightleftharpoons 2NO_2[/tex]

Initial constant               C            -

Equilibrium constant     C          2x

The Kc is given as:

⇒ [tex]K_c = \frac{[NO_2]^2}{[N_2O_4]}[/tex]

         [tex]=\frac{(2x)^2}{C-x}[/tex]

[tex]0.593=\frac{4x^2}{0.88-x}[/tex]

  [tex]4x^2=0.593(0.88-x)[/tex]

  [tex]4x^2=0.512-0.593\ x[/tex]

     [tex]x=0.291[/tex]

hence,

The constant of [tex]NO_2[/tex] will be:

= [tex]2x[/tex]

= [tex]0.583[/tex]

Answer:

net ionic equation

[tex]\boxed{ CaCO_3{}_{(s)} + 2H^{+} {}_{(aq.)} \rightarrow Ca^{2+} {}_{(aq.)} + H_2O_{(l)} + CO_2{}_{(g)} } [/tex]

Answer:

Al is oxidized while Ag is reduced.

Explanation:

The complete molecular equation is;

3Ag2S + 2Al --> 6Ag + Al2S3

Oxidation half equation;

2Al ------> 2Al^3+ + 6e

Reduction half equation;

6Ag^+ + 6e -------> 6Ag

Overall redox reaction equation;

2Al + 6Ag^+ ----->2Al^3+ + 6Ag

Hence; Al is oxidized while Ag is reduced.

Answer:

Like many common group 2 metal carbonates, magnesium carbonate reacts with aqueous acids to release carbon dioxide and water

 MgCO3 + 2 HCl → MgCl2 + CO2 + H2O.

The procedure to obtain pure magnesium chloride from the reaction is as thus

Step 1: Reaction

- Leave the dilute hydrochloric acid in a beaker.

- Add Magnesium carbonate slowly until it is in excess or until no more gas seem to be getting liberated.

Step 2: Filtration

- Filter with filter paper and funnel.

- Filter off the excess magnesium carbonate as magnesium chloride will be in aqueous form (liquid) and will come out with the filtrate. The residue is the excess magnesium carbonate.

Step 3: Crystallization to obtain solid crystals from the filtrate.

- Pour filtrate solution into evaporating dish/basin

- Provide heat using Bunsen burner

- Pour solution into an evaporating basin and heat over a water bath

- Stop heating when crystals start to form

allow water to evaporate until pure crystals remain.

- Dry crystals using absorbent paper or warm oven.

Precautions

- Use personal protective equipment such as gloves, a lab coat and wear eye protection, especially when heating.

- Avoid inhaling unnecessary gases during the whole process.

Answer:Nhóm gồm tất cả các kim loại tan trong axit sunfuric đặc nóng nhưng không tan trong axit sunfuric lo

Al, Cu, Au.

Al, Fe, Cr.

Ag, Fe, Pt.

Ag, Cu, Hg.

Explanation:

Answer:

B. The amount of produd obtained/amount possible * 100

Explanation:

In chemistry, the yield of a chemical reaction is the quantity or amount of products obtained in that chemical reaction. It is calculated by using the following formula:

Percentage yield = Actual yield/theoretical yield × 100

- The actual yield is the amount of products got from a chemical reaction

- The theoretical yield is the amount of product got from using the balanced equation (stoichiometry).

Answer:

have the same number of protons

Answer:

С. form chains or rings by bonding to itself and other atoms.

Explanation:

Carbon is an element in group 4 of the periodic table with unique bonding properties. Carbon posseses 4 valence electrons in its outer shell. This enables carbon to form covalent bonds with the atoms of other elements e.g. nitrogen, phosphorus, oxygen, hydrogen etc.

Carbon can also combine covalently with other carbon atoms i.e. C-C to form long chains and rings in a process called CATENATION. This unique property of carbon makes it the only element that can form so many different compounds.

Answer:

Strong acids react faster whereas weak acids take time to react with any base.

Strong acids are good conductors of electricity on contrary weak acids are not too good as conductors of electricity.

Strong acid passes electricity faster whereas weak acids are slow conductors.

Strong acids are not edible but weak acids are edible.

Strong acids have ph value ranging between 0 to 3 but the ph value of weak acids ranges between 5 to below 7.

Answer:

On a Plateu on a heating curve phase changes are occuring

Explanation:

The first Phase is melting during which the temrature stays the same while water melts.Other phase changes are freezing sublimation Vaourization condensation and deposition

Answer:

2.5 atm

Explanation:

P = Pressure

V = Volume

P1V1 = P2V2

1 x 5 = P2 x 2

5 = P2 x 2

Divide both sides by 2

5/2 = P2 x 2/2

P2 = 2.5

Answer:

20

Explanation:

calculated saturated solutions

Answer:

KI + Cl2 = KCl + I2

Explanation:

hope this helps!!!

Answer:

2KI +Cl₂ → 2KCl +I₂

Explanation:

Potassium ion: K+

Iodide ion: I-

Thus, potassium iodide is KI.

Chlorine exist as a diatomic molecule thus it is written as Cl₂.

Chloride ion: Cl-

Thus, potassium chloride is KCl.

Iodine also exist as a diatomic molecule, thus it is written as I₂.

Write an unbalanced equation:

KI +Cl₂ → KCl +I₂

Now balance by ensuring the number of atoms of each element on each side is the same.

LHS

K: 1 ×2= 2

I: 1 ×2= 2

Cl₂: 2

RHS:

K: 1 ×2= 2

I: 2

Cl: 1 ×2= 2

Thus, the balanced equation is:

2KI +Cl₂ → 2KCl +I₂

Answer:

The oxidation state of N in the KNO3 is +5

Explanation:

Oxidation rules:

1. Oxygen is -2, unless in peroxides.

2. Group 1 metals = +1

3. Group 2 metals = +2

4. If the molecule is neutral, all of the oxidation numbers have to add up to zero.

5. If the molecule is charged, all of the oxidation numbers have to add up to the charge of the molecule.  

So, the given formula represents the salt compound formula unit of potassium nitrate:  KNO3  

The formula unit is uncharged.

From our rules, we know that,

O = -2

And we can find K on the periodic table, in the first group, thus giving it a +1 charge. Now let's put it all together.

K = +1

N = x

O = -2

Let's take into account the number of atoms of each element we have and make an equation since we know everything has to add up to zero since the molecules are neutral.

+1 +x+3 (-2) = 0 (notice we multiplied 3 by -2 because in the formula we have 3 atoms of oxygen with -2 charge each)

x - 5 = 0

x = 5

Therefore, the oxidation number of N in KNO3 is +5.

Answer:

Sulphur

Explanation:

1s² 2s² 2p⁶ 3s² 3p⁴

So in total ya got 16 electrons

3===> defines the period

4+12===> defines the group

and boom, there ya got yaself an element called sulphur

Answer:

Explanation:

Formula

The current = charge / time

The charge is in coulombs

The time has to be in seconds.

1 minute = 60 seconds

2 minutes = 120 seconds.

charge = 180 coulombs

current = 180 / 120

current = 1.5 amperes.

Explanation:

Solution is a homogenous mixture of two or more substances in relative amounts that can be varied continuously up to what is called the limit of solubility.

A mixture in which one substance is divided into minute particles (called colloidal particles) and dispersed throughout a second substance

A suspension is a heterogeneous mixture of a finely distributed solid in a liquid. The solid is not dissolved in the liquid, as is the case with a mixture of salt and water.

Here, we have been given that;

Hence, we can note that,

(n) = 32.05

[tex] \\ [/tex]

Thus,

Hence, molarity of the given solution will be 32.05 mg/L.