Select all examples that apply as a physical changes in properties (please help)

an element is a substance that cannot be split into simpler substances by a chemical means . for example - hydrogen, oxygen, nitrogen, carbon, iron, aluminium, copper, silver and gold some example of elements.

Answer:

The mole fraction of NaOH in an aqueous solution that contain 22.9% NaOH by mass=0.882

Explanation:

We are given that

Aqueous solution that contains 22.9% NaOH by mass means

22.9 g NaOH in 100 g solution.

Mass of NaOH(WB)=22.9 g

Mass of water =100-22.9=77.1

Na=23

O=16

H=1.01

Molar mass of NaOH(MB)=23+16+1.01=40.01

Number of moles =[tex]\frac{Given\;mass}{Molar\;mass}[/tex]

Using the formula

Number of moles of  NaOH[tex](n_B)=\frac{W_B}{M_B}=\frac{22.9}{40.01}[/tex]

[tex]n_B=0.572moles[/tex]

Molar mass of water=16+2(1.01)=18.02g

Number of moles of water[tex](n_A)=\frac{77.1}{18.02}[/tex]

[tex]n_A=4.279 moles[/tex]

Now, mole fraction of NaOH

=[tex]\frac{n_B}{n_B+n_A}[/tex]

[tex]=\frac{4.279}{0.572+4.279}[/tex]

=0.882

Hence, the mole fraction of NaOH in an aqueous solution that contain 22.9% NaOH by mass=0.882

Answer:

See Explanation

Explanation:

The way by which a metal is obtained from its ore is determined by the chemical reactivity of the metal.

Metals that are highly reactive are chiefly obtained by electrolysis of the metal salt. These metals are found high up in the metal activity series.

Metals that are at the middle of the series are moderately reactive and are obtained by electrolysis or by reduction since they still form ionic salts.

Metals that are far lower in the series can only be obtained by heating them in air because they are mostly unreactive.

Hence, moderately reactive metals at the middle of the series are not obtained by roasting in air.

Answer:

Gamma rays and X-rays

Explanation:

All the things she said

All the things she said

Running through my head

Running through my head

Running through my head

All the things she said

All the things she said

Running through my head

Running through my head

All the things she said

This is not enough

This is not enough

Answer:

D. the capacity to do work

Explanation:

the basic definition of energy is the ability to do work

Answer:

There are 3 significant figures on this one.

Answer:

bismuth

Explanation:

i think if not i am so sorry

Explanation:

2/1×1.25

=2.5 mole of NaCl are produced

weight of NaCl produced = moles × molar mass of NaCl

weight of NaCl produced = 2.5×58.5

weight of NaCl produced =146.5 grams

Answer:

1.25 moles of magnesium chloride are produced

Explanation:

Based on the reaction:

Mg(s) + 2HCl (aq) → MgCl₂(s) + H₂(g)

1 mole of magnesium, Mg, reacts with 2 moles of hydrochloric acid, HCl, to produce 1 mole of magnesium chloride, MgCl₂ and 1 mole of hydrogen gas.

To solve this question we have to tak, from the chemical equation:

2 mol HCl = 1mol MgCl₂

That means, the moles of MgCl₂ produced from 2.50mol HCl are:

2.50 mol HCl * (1mol MgCl₂ / 2mol HCl) =

Answer:

Al is oxidized

Cu is reduced

Answer:

here

Cu is reduced

and

Al is oxidised

hope this will help you

have a nice day

Answer:

Explanation:

If the choices are:

A. Molarity is defined as moles of solute per liter of solvent.

B. % by mass is defined as grams of solute per 100 g of solvent.

C. % by volume is defined as grams of solute per 100 L of solution.

D. Molarity is defined as moles of solute per liter of solution.

E. All of the above.

then the ans is E

Answer:

They are inversely related.

Explanation:

Answer:

B: it has a high heat capacity

Explanation:

When any material has a high specific heat capacity/ heat capacity, it doesn't heat or cool very fast. So water can absorb more heat from the engine and can keep the engine cool or at low temperature for a longer period of time.

Answer:

D. Solids

Explanation:

Answer:

B

Explanation:

When water evaporate, it moves faster

Answer:

1. 92.5 ml

2. 3.13 L

3. 524.48 K

Explanation:

1. Using Boyle's law equation:

P1V1 = P2V2

Where;

P1 = initial pressure (atm)

V1 = initial volume (ml)

V2 = final volume (ml)

P2 = final pressure (atm)

Based on the information in question 1: P1 = 3.7atm, P2 = 1atm, V1 = 25 mL, V2 = ?

3.7 × 25 = 1 × V2

92.5 = V2

V2 = 92.5ml

2. Using Charles law equation as follows:

V1/T1 = V2/T2

Where;

V1 = initial volume (L)

V2 = final volume (L)

T1 = initial temperature (K)

T2 = final temperature (K)

Based on the information provided: V1 = 3L, V2 = ?, T1 = 25°C = 25 +273 = 298K, T2 = 38°C = 38 + 273 = 311K

3/298 = V2/311

Cross multiply

298 × V2 = 3 × 311

298V2 = 933

V2 = 933 ÷ 298

V2 = 3.13L

3. Using Charles law equation as follows:

V1/T1 = V2/T2

Where;

V1 = initial volume (L)

V2 = final volume (L)

T1 = initial temperature (K)

T2 = final temperature (K)

Based on the information provided; V1 = 1.72 L, T1 = 18°C = 18 + 273 = 291K, T2 = ?, V2 = 3.1L

1.72/291 = 3.1/T2

Cross multiply

1.72 × T2 = 291 × 3.1

1.72T2 = 902.1

T2 = 902.1 ÷ 1.72

T2 = 524.48K

Answer:

HCl, H2O, and NH3 are the most polar of these, so they won't behave ideally because the particles have greater attractive forces between them. How does the kinetic-molecular theory explain the pressure exerted by gases? ... Particles are always in motion and when they are contained, they are elastic collisions.

The particles have high intermolecular forces, reducing the elasticity of their collisions.

Polar molecules are formed when a high electronegative atom combined with a less electronegative atom.

Ammonia, sulfur dioxide, hydrogen sulfide, are polar gases.

The non-polar gases are inert gas or noble gas.

The polar compounds are asymmetrically array.

Thus, the correct option is 4, The particles have high intermolecular forces, reducing the elasticity of their collisions.

Learn more about polar gases, here:

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Answer:

Showing changing colour of the skin who exposed to the radiation.

Explanation:

Chernobyl Episode 4 portray the traumatic effects of the situation on people by showing changing colour of skin of the staff present at nuclear reactor at the time of explosion. The people who exposed to the radiations of the nuclear reactor will die later in the hospital which shows that radiation of nuclear reactor is hazardous and damaging for the skin as well as for the body of humans.

Answer:

V = 25.7 L.  

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to solve for the volume of hydrogen, by firstly calculating the moles of this gas produced by 37.6 g of magnesium, according to the 1:1 mole ratio between them:

[tex]n_{H_2}=37.6gMg*\frac{1molMg}{24.305gMg}*\frac{1molH_2}{1molMg}=1.55molH_2[/tex]

Now, we use the ideal gas equation:

[tex]PV=nRT[/tex]

To solve for the volume, and obtain:

[tex]V=\frac{nRT}{P}\\\\V=\frac{1.55mol*0.08206\frac{atm*L}{mol*K}*293.15K}{1.45atm}\\\\V=25.7L[/tex]

Regards!

Answer:the third one

Explanation:

To Find :

How many moles are in [tex]7.12 \times 10^{21}[/tex] atoms of iron.

Given :

We know, 1 mole of any element or compound contains exactly [tex]N_A[/tex] ( Avogadro's Number ) atoms/compound .

Now, [tex]N_A = 6.022 \times 10^{23}[/tex]

So, number of moles in given number of atoms are :

[tex]n = \dfrac{6.022 \times 10^{23}}{7.12 \times 10^{21}}\\\\n = 1.18 \times 10^{-2} \ mol[/tex]

Hence, this is the required solution.

Answers:

There's many factors, such as the temperature, rainfall, food available, and the surrounding terrain, that all can effect an animal's characteristics.

Answer:

sidjnfjdueirb sidisjsiwijejdkdodif

Answer:

(1s)^2 (2s)^2 (2p)^3

Explanation:

Nitrogen has 7 electrons. Hence, the structure will be,

=>(1s)^2 (2s)^2 (2p)^3

Hope it helps:)

The electronic configuration is used to explain the orbitals of an atom and it helps to determine the physical and chemical properties of the elements. The electronic configuration of Nitrogen is 1s² 2s² 2p³. The correct option is B.

The distribution of electrons in the atomic orbitals is given by the electronic configuration. It is a standard notation in which all the electrons holding atomic subshells are arranged in a sequence. Each element has a unique electronic configuration.

The electronic configuration of an element can be written in two ways, in standard notation, and in condensed form. In the case of elements with larger atomic numbers, the electronic configuration becomes lengthy in standard notation. So in such cases condensed form is generally used.

The electronic configuration of 'N' of atomic number 7 in standard form is 1s² 2s² 2p³ and in condensed form it is [He] 2s²2p³.

Thus the correct option is B.

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Answer:

See Explanation

Explanation:

The question is asking us about how to determine which compounds are ionic and which compounds are covalent.

First, we must understand that ionic compounds are formed between metals and nonmetals having a large difference in electronegativity.

Secondly, covalent compounds are mostly formed between atoms of nonmetal elements.

If we keep these things in mind, we can see that compounds such as NaCl and CaCl2 are ionic while CO2 and SO3 are covalent.

Answer:

Explanation:

The pH of a solution can be found by using the formula

[tex]pH = - log [ { H_3O}^{+}][/tex]

From the question we have

[tex]ph = - log(5.67 \times {10}^{ - 4} ) \\ = 3.2464[/tex]

We have the final answer as

Hope this helps you

Answer:

subscript is 3

Explanation:

the  subscript is the number that is slightly lower than a # which in this case it's O

this indicates that there's 3 oxygen atoms

Answer:

the answer is 1 ‍♀️

Explanation:

Answer: Carbon dioxide reacts with calcium hydroxide solution to produce a white precipitate of calcium carbonate. Limewater is a solution of calcium hydroxide. If carbon dioxide is bubbled through limewater, the limewater turns milky or cloudy white.

Explanation:

****Isra****

Nuclear fusion is not yet a practical energy source due to no available environment on the earth.

Nuclear fusion is not yet a practical energy source because it requires very hot environment which is not possible on the earth. Nuclear fusion reactions occur only on the sun because the temperature is very high and environment is suitable for the reaction,

So we can conclude that Nuclear fusion is not yet a practical energy source due to no available environment on the earth.

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Answer:

b) 4.37x10-3 M. is the correct answer

See the attached page, I've shown the calculation over there