(plsss help meh.) Describe how you could find the density of a gold crown.

Answer:

The element in question here is Scandium, with an atomic number of 21. It is situated in Group 3 and Period 4 of the Periodic Table.

Explanation:

Hope this helped!

The concentration in mol L-l (M) = 0.717

Given

12% solution of tetrahydrate magnesium chloride (MgCl₂)

Required

The concentration

Solution

Tetrahydrate magnesium chloride (MgCl₂)⇒MgCl₂.4H₂O

MW = Ar Mg+2. Ar Cl+8. Ar H + 4. Ar O

MW=24.31 + 2 x 35.45 + 8 x 1.01 + 4 x 16

MW=24.31+70.9+8.08+64

MW=167.29 g/mol

12% solution = 12 % m/v = 12 g in 100 ml solution

For 1 L solution :

[tex]\tt \dfrac{1}{0.1}\times 12~g=120~g[/tex]

The concentration in g/L = 120 g/L

Convert grams to moles :

[tex]\tt mol=\dfrac{120}{167.29}=0.717[/tex]

Answer:

Copper

Explanation:

Because copper conducts a lot of electricity, and gets the most electrons

Answer:

H:H

Explanation:

Answer:

A

Explanation:

i had answer it and it was A

Answer:

Number of moles = 0.057 × 10⁻⁷  mol

Explanation:

Given data:

Mass of SiO₂ = 3.4 × 10⁻⁷ g

Number of moles = ?

Solution:

Number of moles = mass/molar mass

Molar mass of SiO₂ = 60 g/mol

by putting values,

Number of moles =  3.4 × 10⁻⁷ g / 60 g/mol

Number of moles = 0.057 × 10⁻⁷  mol

i dont see any processes below

Answer:

Heat and pressure

Explanation:

got it on study island

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:

[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:

3

2

Explanation:

3O2 => 2O3

the equation is balancing

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.

To learn more about physical and chemical properties, visit the below link:

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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:

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.

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: Peer-reviewed journal article is the most useful because the information in them had been carefully scrutinized and aproved by people who are experts in that particular field.

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:

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:

B

Explanation:

by simlfying it you get HCO2

Answer:

Mole, also spelled mol, in chemistry, a standard scientific unit for measuring large quantities of very small entities such as atoms, molecules, or other

Answer:

Mole, also spelled mol, in chemistry, a standard scientific unit for measuring large quantities of very small entities such as atoms, molecules, or other specified particles.

Explanation:

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

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: B

We use stoichiometric amounts of P4 and PH3

NO.9) It's actual yield

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.

Learn more about chemical equation,here:

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Answer:

exothermic reaction

Explanation:

because it occurs in the presence of heat

Answer is

Chloromethane

Explanation: because c stand for carbon an the h stands for hydrogen and ci stands for

Chemical ionization

Answer:

[tex]\boxed {\boxed {\sf C. \ 4}}[/tex]

Explanation:

First, define some important terms.

We know the mass number is 9. So, the sum of protons and neutrons is 9.

We also know the atoms has 5 neutrons. Therefore, the rest must be protons.

Subtract the 5 neutrons from the overall mass number of 9.

There are 4 protons, so the atomic number is also 4. This atom is beryllium.

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]