HELP 20 POINTS

What is the frequency of an Electromagnetic wave has with wavelength 2.94 x 10^-8 cm?

The chemist weigh out 35.51 g Na2SO4

Given

0.250 moles of Na2SO4

Required

weight of Na2SO4

Solution

A mole is a number of particles(atoms, molecules, ions)  in a substance

This refers to the atomic total of the 12 gr C-12  which is equal to 6.02.10²³, so 1 mole = 6.02.10²³ particles  

Moles of a substance can also be determined from its molecular weight

[tex]\tt mol=\dfrac{mass}{MW}[/tex]

For 0.250 moles of Na2SO4, mass =

[tex]\tt mass=mol\times MW\\\\mass=0.25\times 142,04 g/mol\\\\mass=35.51~g[/tex]

Answer:

3

Explanation:

Sodium is not a gas, it is a Alkali Metal. I recommend studying the sections of the periodic table to help remember what each element should be.

Hope this helps.

Answer:

Propane gas plus oxygen gas produces water and carbon dioxide.

Explanation:

This is the initial chemical equation: C3H8 + O2 = CO2 + H2O

This is the balanced chemical equation: C3H8 + 5 O2 = 3 CO2 + 4 H2O

C3H8 + O2 → CO2 + H2O

C3H8 + 5O2 → 3CO2 + 4H2O

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Answer:

physical property

Chemical property

melting point

Reactivity with a strong acid

Explanation:

The ability to conduct electricity is a physical property of copper. Most electrical cables are made of copper owing to its high electrical conductivity.

The rusting of iron is a chemical reaction. Rust is actually hydrated iron III oxide. Hence it is a chemical property of iron.

The melting points of metals can be used to classify them. The greater the density of metals, the higher their melting point.

The ability of metals to react with acids separates metals into highly reactive, moderately reactive and unreactive metals.

Copper shows physcal property & iron shows chemical property.

Physical properties are those properties which are seen by the eye due to change in the outermost appearance, whereas chemical properties are those which are shown due to change in the internal composition.

In the question, it is given that copper metal has a ability to conduct electricity and this property of metal is the physical property, as due to conduction their identity is not changing.

It is also given that iron is showing rusting due to the formation of iron oxide, so it a chemical property as identity of iron changes.

So, scientists characterize certain metals, they investigate physical properties like melting point, conductivity, density, etc. and chemical properties like reactivity with acid, base, oxygen, etc.

Hence, the ability to conduct electricity is a physical property of Cu and the ability of iron to rust is a chemical property.

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i dont see any processes below

Answer:

Heat and pressure

Explanation:

got it on study island

Answer:

Suns gravity

Explanation:

Answer: 2021

B

The Sun's gravity

Explanation: Just took the big test

1. A radical is a reactive intermediate with a single ____________ electron, formed by ____________ of a covalent bond.

1. A: Unpaired, and homolysis

2. Allylic radicals are stabilized by ____________ , making them ____________ stable than tertiary radicals.

2. A: Resonance, and more

3. A compound that contains an especially weak bond that serves as a source of radicals is called a radical ____________ .

3. A: Initiator

4. Treatment of cyclohexene with N-bromosuccinimide in the presence of light leads to ____________ by ____________ intermediates.

4. A: Allylic substitution by radical

Answer:

1. Synthesis

2. Decomposition

3. Single replacement

4. Synthesis

5. Decomposition

6. Synthesis

Explanation:

Kind of a hard picture to look at but let me define each chemical reaction:

Synthesis:

a + b ---> ab   In synthesis elements/compounds come together to form new                compounds

Decomposition:

ab ---> a + b   In decomposition a compound breaks down to form 2 elements/compounds

Single replacement:

a + bc ---> b + ac   In a single replacement one element/compound takes the place of another element/compound.

Double replacement

ab + cd ---> ad + bc In a double replacement 2 compounds exchange different elements/compounds.

Now, let's go through the assignment

1. P + O2 --> P4O10  This is a synthesis reaction because the two elements (P and O) came together to form one compound.

2. HgO ---> Hg + O2  This is a decomposition reaction because HgO broke into separate elements Hg and O.

3. Cl2 + NaBr ---> NaCl + Br2  This is a single replacement reaction because chlorine (Cl) replaced the spot of bromine (Br) to bond with sodium (Na).

4.  Mg + O2 ---> MgO  This is a synthesis reaction because two elements (Mg and O) came together to form one compound.

5. Al2O3 ---> Al + O2  This is a decomposition reactions because Al2O3 broke into separate elements Al and O.

6. H2 + N2 ---> NH3  This is a synthesis reaction because two elements (H and N) came together to form one compound.

I hope this helps!!

- Kay :)

Given chemical equations are of  following types which are given in serial order as synthesis,decomposition,replacement,synthesis,decomposition and synthesis reactions respectively.

1. It is a synthesis reaction because the two elements (P and O) came together to form one compound.

2. It is a decomposition reaction because HgO broke into separate elements Hg and O.

3. It is a single replacement reaction because chlorine (Cl) replaced the spot of bromine (Br) to bond with sodium (Na).

4.  It is a synthesis reaction because two elements (Mg and O) came together to form one compound.

5. It is a decomposition reactions because aluminium oxide broke into separate elements Al and O.

6. It is a synthesis reaction because two elements (H and N) came together to form one compound.

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#SPJ4

The complete question is attached to this answer

Answer:

2.75 * 10^-5 m

Explanation:

The energy of the absorbed photon = ΔE

ΔE = - Ry (1/n^2 final - 1/n^2initial)

Given that Ry = 2.18 *10^-18 J

nfinal = 9

ninitial =8

ΔE = - 2.18 *10^-18 (1/9^2- 1/8^2)

ΔE = - 2.18 *10^-18 (0.0123 - 0.0156)

ΔE = 7.194 * 10^-21 J

But

ΔE =hc/λ

h = 6.6 *10^-34Js

c= 3 * 10^8 ms-1

λ= the unknown

λ= hc/ΔE

λ= 6.6 *10^-34 * 3 * 10^8/ 7.194 * 10^-21

λ= 2.75 * 10^-5 m

Answer:

true

Explanation:

Answer:

True

Explanation:

In a displacement reaction, more reactive element displaces less reactive element. Whereas in a double displacement reaction there is exchange of ions of two compounds.

390 g KNO₃

Atomic Structure

Pre-Algebra

Order of Operations: BPEMDAS

Step 1: Define

2.3 × 10²⁴ formula units KNO₃

Step 2: Identify Conversions

Avogadro's Number

Molar Mass of K - 39.10 g/mol

Molar Mass of N - 14.01 g/mol

Molar Mass of O - 16.00 g.mol

Molar Mass of KNO₃ - 39.10 + 14.01 + 3(16.00) = 101.11 g/mol

Step 3: Convert

[tex]2.3 \cdot 10^{24} \ formula \ units \ KNO_3(\frac{1 \ mol \ KNO_3}{6.022 \cdot 10^{23} \ formula \ units \ KNO_3} )(\frac{101.11 \ g \ KNO_3}{1 \ mol \ KNO_3} )[/tex] = 386.172 g KNO₃

Step 4: Check

We are given 2 sig figs. Follow sig fig rules and round.

386.172 g KNO₃ ≈ 390 g KNO₃

Answer:

Coefficients represents no of moles while subscripts represent no of atoms.

Answer:

Coefficients came before formula . Example = 4CO means there are 4 molecules of carbonmonooxide.

Subscripts came after and below the formula . Example = Oxygen gas in which 2 is a subscript which means there are 2 atoms of Oxygen in 1 molecule of Oxygen i.e. oxygen gas

Answer: There will be 9.9632 × 10⁻¹⁸ moles of Copper in 6,000,000 atoms of Copper.

Answer:

D. (16.0 g + 16.0 g) × 100% / (32.1 g + 16.0 g + 16.0 g) = 49.9%

Explanation:

Step 1: Detemine the mass of O in SO₂

There are 2 atoms of O in 1 molecule of SO₂. Then,

m(O) = 2 × 16.0 g = 16.0 g + 16.0 g = 32.0 g

Step 2: Determine the mass of SO₂

m(SO₂) = 1 × mS + 2 × mO = 1 × 32.1 g + 2 × 16.0 g = 32.1 g + 16.0 g + 16.0 g = 64.1 g

Step 3: Detemine the mass percent of oxygen in SO₂

We will use the following expression.

m(O)/m(SO₂) × 100%

(16.0 g + 16.0 g) × 100% / (32.1 g + 16.0 g + 16.0 g) = 49.9%

Answer:

16.0 g + 16.0 g) × 100% / (32.1 g + 16.0 g + 16.0 g) = 49.9%

Explanation:

Answer:

[tex]CaS[/tex]

Explanation:

Hello!

In this case, since calcium's oxidation state when forming ionic bonds is +2 and sulfur's oxidation state when bonding those bonds is -2, for the required formula we write:

[tex]Ca^{2+}S^{2-}[/tex]

Now, since they have the same charge number, we infer the ionic compound formed when they bond is calcium sulfide:

[tex]CaS[/tex]

Best regards!

Answer:

Hydrogen

Explanation:

Helium has an atomic number Z = 2, that is, it has 2 protons. Since it is electrically neutral it also has 2 electrons. Thus, the electron configuration of helium is 1s².

Hydrogen has an atomic number Z = 1, that is, it has 1 proton. Since it is electrically neutral it also has 1 electron. Thus, the electron configuration of hydrogen is 1s¹.

If hydrogen gains a single extra electron to form H¹⁻, it acquires the same electron configuration than helium.

Answer:

Explanation:

The initial volume can be found by using the formula for Boyle's law which is

[tex]P_1V_1 = P_2V_2[/tex]

Since we are finding the initial volume

[tex]V_1 = \frac{P_2V_2}{P_1} \\[/tex]

From the question we have

[tex]V_1 = \frac{8.73 \times 18.4}{3.89} = \frac{160.632}{3.89} \\ = 41.293573...[/tex]

We have the final answer as

Hope this helps you

Answer:

The enthalpy of neutralization and its relation to esterification​ is explained below in details.

Explanation:

The conventional enthalpy variation of neutralization is the enthalpy exchange when extracts of an acid and an alkali respond together under conventional circumstances to generate 1 mole of water. Remark that the enthalpy change of neutralization is always estimated per mole of water produced.

Answer:

I think it's true. But I'm not sure

Answer:

True

Explanation:

Answer:

12.3 L

Explanation:

Now we have that the rate of diffusion of the saturated hydrocarbon is R1

Rate of diffusion of sulphur dioxide is R2

Molar mass of hydrocarbon is M1

Molar mass of sulphur dioxide is 64 gmol-1

From Graham's law;

R1/R2 = √64/M1

2/1 =√64/M1

(2/1)^2 = (√64/M1)^2

4/1 = 64/M1

4M1 =64

M1 = 16

To obtain the number of moles of the gas;

(n*12) + (2n + 2) 1 = 16

12n + 2n + 2 = 16

14n + 2 = 16

14n = 16 - 2

n = 14/14

n = 1

Hence the hydrocarbon is CH4

Volume occupied by CH4 at STP = 22.4 L

Hence;

P1 = 1 atm

T1 = 273 K

V1 = 22.4 L

T2 = 300 K

P2 = 2 atm

V2 = ?

P1V1/T1 = P2V2/T2

P1V1T2 = P2V2T1

V2 = P1V1T2/P2T1

V2 = 1 * 22.4 * 300/2 * 273

V2 = 12.3 L

The volume occupied by the hydrocarbon at 27 °C and 2 atm is 12.31 L

Let the hydrocarbon be initially at standard temperature and pressure (STP)

Thus, we can obtain the new volume of the hydrocarbon by using the combined gas equation as illustrated below:

P₁V₁ / T₁ = P₂V₂ / T₂

(1 × 22.4) / 273 = (2 × V₂) / 300

22.4 / 273 = (2 × V₂) / 300

Cross multiply

273 × 2 × V₂ = 22.4 × 300

546 × V₂ = 6720

Divide both side by 546

V₂ = 6720 / 546

V₂ = 12.31 L

Thus, the volume occupied by the hydrocarbon at 27 °C and 2 atm is 12.31 L

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Answer:

1. 9.45 g

2. 66.9%

Explanation:

The balanced equation for the reaction is given below:

Cu(s) + 4HNO3(aq) —> Cu(NO3)2(aq) + 2NO2(g) + 2 H2O(l)

Next, we shall determine the mass of Cu that reacted and the mass of Cu(NO3)2 produced from the balanced equation. This can be obtained as follow:

Molar mass of Cu = 63.5 g/mol

Mass of Cu from the balanced equation

= 1 × 63.5 = 63.5 g

Molar mass of Cu(NO3)2 = 63.5 + 2[14 + (3×16)]

= 63.5 + 2[14 + 48]

= 63.5 + 2[62]

= 63.5 + 124

= 187.5 g/mol

Mass of Cu(NO3)2 from the balanced equation = 1 × 187.5 = 187.5 g

Summary:

From the balanced equation above,

63.5 g of Cu reacted to produce 187.5 g of Cu(NO3)2.

1. Determination of the theoretical yield of Cu(NO3)2. This can be obtained as follow:

From the balanced equation above,

63.5 g of Cu reacted to produce 187.5 g of Cu(NO3)2.

Therefore, 3.20 g of Cu will react to produce = (3.20 × 187.5) / 63.5 = 9.45 g of Cu(NO3)2.

Thus, the theoretical yield of Cu(NO3)2 is 9.45 g.

2. Determination of the percentage yield of Cu(NO3)2.

Actual yield of Cu(NO3)2 = 6.32 g

Theoretical yield of Cu(NO3)2 = 9.45 g.

Percentage of the Cu(NO3)2 =?

Percentage yield = Actual yield /Theoretical yield × 100

Percentage yield of Cu(NO3)2 = 6.32/9.45 × 100

Percentage yield of Cu(NO3)2 = 66.9%

The theoretical yield of Cu(NO₃)₂ is 9.445 g

The percent yield of Cu(NO₃)₂ is 66.91%

From the question.

We are to determine the theoretical yield of Cu(NO₃)₂,

First and foremost, we will write the balanced chemical equation for the reaction properly

The balanced chemical equation for the reaction is

Cu(s) + 4HNO₃(aq) → Cu(NO₃)₂(aq) + 2NO₂(g) + 2H₂O(l)

This means

1 mole of Cu will react with 4 moles of HNO₃ to produce 1 mole of Cu(NO₃)₂, 2 moles of NO₂ and 2 moles of H₂O

To determine the theoretical yield of Cu(NO₃)₂,

First, we will determine the number of moles of Cu that reacted

Mass of Cu = 3.20 g

Molar mass of Cu = 63.546 g/mol

From the formula

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

∴ Number of moles of Cu = [tex]\frac{3.20}{63.546}[/tex]

Number of moles of Cu present = 0.050357 moles

The number of moles of Cu that reacted is 0.050357 moles

Since,

1 mole of Cu will react with 4 moles of HNO₃ to produce 1 mole of Cu(NO₃)₂

Then,

0.050357 moles of Cu will react with 0.201428 moles of HNO₃ to produce 0.050357 moles of Cu(NO₃)₂

∴ 0.050357 moles of Cu(NO₃)₂ will be produced during reaction

Now, for the theoretical yield of Cu(NO₃)₂  

From the formula

Mass = Number of moles ×  Molar mass

Molar mass of Cu(NO₃)₂ = 187.56 g/mol

∴ Theoretical yield of Cu(NO₃)₂ = 0.050357 × 187.56

Theoretical yield of Cu(NO₃)₂ = 9.445 g

Hence, the theoretical yield of Cu(NO₃)₂ is 9.445 g

For the percent yield of Cu(NO₃)₂

[tex]Percent \ yield = \frac{Actual \ yield}{Theoretical \ yield } \times 100 \%[/tex]

From the question

Actual yield = 6.32 g

But,

Theoretical yield = 9.445 g

∴ Percent yield of Cu(NO₃)₂ = [tex]\frac{6.32}{9.445} \times 100\%[/tex]

Percent yield of Cu(NO₃)₂ = [tex]\frac{632}{9.445}\%[/tex]

Percent yield of Cu(NO₃)₂ = 66.91%

Hence, the percent yield of Cu(NO₃)₂ is 66.91%

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Answer:

a. chemical change

Explanation:

A chemical change can cause an odor, however a physical change cannot, and the use of thermal energy will only make an object colder, not give it an odor.

Initial temperature = -189.4  °C

Given

the volume of a gas is  changed from 3.6 L to 15.5 L

final temperature = 87 °C = 87+ 273 = 360 K

Required

initial temperature

Solution

Charles's Law

When the gas pressure is kept constant, the gas volume is proportional to the temperature  

[tex]\tt \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}[/tex]

[tex]\tt T_1=\dfrac{V_1.T_2}{V_2}\\\\T_1=\dfrac{3.6\times 360}{15.5}\\\\T_1=83.6~K=-189.4^oC[/tex]

Answer:

-189.55°C

Explanation:

Given data:

Initial volume of gas = 3.6 L

Final volume of gas = 15.5 L

Initial temperature = ?

Final temperature = 87°C (87+273 = 360 K)

Solution:

The given problem will be solve through the Charles Law.

According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.

Mathematical expression:

V₁/T₁ = V₂/T₂

V₁ = Initial volume

T₁ = Initial temperature

V₂ = Final volume  

T₂ = Final temperature

Now we will put the values in formula.

V₁/T₁ = V₂/T₂

T₁  = V₁T₂  /V₂

T₁   = 3.6 L × 360 K / 15.5 L

T₁   = 1296 L.K / 15.5 L

T₁  = 83.6 K

Kelvin to °C:

83.6 K - 273.15 = -189.55°C

Answer:

exothermic reaction

Explanation:

because it occurs in the presence of heat