You have a sample of gold that contains 0.2 moles of gold (Au). How many gold atoms are present in the sample. HINT: Gold atoms represents the number of particles."

1.20 x 10^23 atoms

3.3 x 10^-25 atoms

1.01 x 10^-3 moles

Answer: The amino acid that has a positively charged R group are LYSINE and ARGININE.

Explanation:

AMINO ACIDS are the basic structural units of proteins. Each amino acid contains an amino group ( -NH2) and a carboxyl group (-COOH) in its molecule. The carbon atom of amino acid to which the functional groups are attached is know as the alpha-carbon. In neutral solution, amino acids are mainly in the form of dipolar ions. Amino acids can be prepared through hydrolysis of protein by boiling with dilute hydrochloric acid.

Amino acids can be classified according to the chemical properties of its side chain (R group) at pH 7, these include:

--> Amino acids with POSITIVELY CHARGED R group

--> Amino acids with negatively charged R group

--> Amino acids with neutral polar R group

--> Amino acids with nonpolar aliphatic R group.

Amino acids with POSITIVELY CHARGED R group are those amino acids that has side chains which contain nitrogen and resemble ammonia, which is a base. Their pKa's are high enough that they tend to bind protons, gaining a positive charge in the process. Example include LYSINE and ARGININE.

Answer:

20,8ml  NaCl 6M

Explanation:

C1V1 = C2V2

Answer:

electrophilic addition and

nucleophilic addition.

Answer:

the two types of addition compoundsare:

1.electrophilic addition

2. nucleophilic addition.

Answer:

an estimate of the strength of a bond.

Explanation:

The bond order is given as;

1/2(number of bonding electrons - number of anti bonding electrons)

The bond order tells us about the strength of bond. As the bond order increases, so does the strength of the bond because atoms involved in bonding come closer to each other as the bond length decreases.

Hence, bond order is an index of bond strength. Triple bonds are stronger than double bonds which are stronger than single bonds.

Answer:

(a) The moles of CuSO₄ is 3.125 × 10⁻³ moles.

(b) The moles of Cu is 3.125 × 10⁻³ moles.

(c) The mass of Cu is 0.2 g.

Explanation:

Given:

Mass of CuSO₄ = 0.5 g

Molar mass of CuSO₄ = 160 g/mol

The given balanced chemical equation is:

[tex]2Al+3CuSO_4\rightarrow 3Cu+Al_2(SO_4)_3[/tex]

Part (a):

Calculating the moles of CuSO₄.

[tex]\text{Moles of } CuSO_4=\frac{\text{Mass of }CuSO_4}{\text{Molar mass of }CuSO_4}\\\\\text{Moles of } CuSO_4=\frac{0.5g}{160g/mol}\\\\\text{Moles of } CuSO_4=3.125\times 10^{-3}mol[/tex]

Thus, the moles of CuSO₄ is 3.125 × 10⁻³ moles.

Part (b):

Calculating the moles of Cu.

From the balanced chemical equation, we conclude that:

As, 3 moles of CuSO₄ reacts to give 3 moles of Cu

So, 3.125 × 10⁻³ moles of CuSO₄ reacts to give 3.125 × 10⁻³ moles of Cu

Thus, the moles of Cu is 3.125 × 10⁻³ moles.

Part (c):

Calculating the mass of Cu.

Mass of Cu = Moles of Cu × Molar mass of Cu

Molar mass of Cu = 64 g/mol

Mass of Cu = (3.125 × 10⁻³ mole) × (64 g/mol)

Mass of Cu = 0.2 g

Thus, the mass of Cu is 0.2 g.

To make the steel less likely to rust, element like chromium is added to it. Therefore, the given statement is correct.

Steel can be described as an alloy composed of iron with a few tenths of a percent of carbon to enhance its strength and fracture resistance. In steel, alloying elements inclusions within the iron act as hardening agents as they stop the movement of dislocations.

Stainless steels are corrosion- and oxidation-resistant but they need an additional 11% chromium. This type of steel is used in buildings, infrastructure, ships, trains, machines, electrical appliances, weapons, and rockets because of its high tensile strength and low cost.

It can take two crystalline forms body-centered cubic and face-centered cubic depending on the temperature. The interaction of the allotropes of iron with elements such as carbon gives the steel its range of unique properties.

Therefore, the given statement is true that chromium is used in steel formation.

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Answer:

Chlorine

Chlorine has two naturally occurring isotopes. In a sample of chlorine, 75.77% of the atoms are Cl-35, with a mass of 34.97amu.

Explanation:

hope it helps thanks❤

Chlorine has two naturally occurring isotopes. In a sample of chlorine, 75.77% of the atoms are Cl-35, with a mass of 34.97amu.

List the known and unknown values ​​and edit the problem. Convert each percentage value into a decimal by dividing it by 100. Multiply this number by the atomic mass of that spot. Mix together each isotope to find the median atomic mass.

To calculate the maximum percentage of each isotope in a sample of something, chemists usually divide the atomic number of a particular isotope by the total number of atoms of all that isotope and multiply the result by 100.

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Coal and Energy obtained from coal are formed as a result of decomposed life matter such as plants

A. Compressed ancient plants

It should be noted that coal is also a type of fossil fuel formed by prolong compaction of fossil material e.g dead plants over millions of years, forest lives etc. and as a result of high pressure and heat acting on these fossil matter they are transformed to fuel.

In summary, fossil fuels are formed as a result of age long compressed matter.

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Answer:

as in shapes

Explanation:

Answer:

14.9 g

Explanation:

Step 1: Write the balanced equation

C₄H₁₀ + 6.5 O₂ ⇒ 4 CO₂ + 5 H₂O

Step 2: Calculate the moles corresponding to 9.57 g of C₄H₁₀

The molar mass of C₄H₁₀ is 58.12 g/mol.

9.57 g × 1 mol/58.12 g = 0.165 mol

Step 3: Calculate the moles of H₂O produced from 0.165 moles of C₄H₁₀

0.165 mol C₄H₁₀ × 5 mol H₂O/1 mol C₄H₁₀ = 0.825 mol H₂O

Step 4: Calculate the mass corresponding to 0.825 mol of H₂O

The molar mass of H₂O is 18.02 g/mol.

0.825 mol × 18.02 g/mol = 14.9 g

Answer:

C8H18 + 25/2O2 ----> 8CO2 + 9H2O

Explanation:

2,3,3-trimethylpentane has the molecular formula C8H18.

The general formula for the combustion of an alkane is;

CnH2n+2 + 3n+1/2O2 ----->nCO2 + (n+1)H2O

In writing a balanced chemical reaction equation, the number of atoms of each element on the left hand side of the reaction equation must be the same as the number of atoms of the same element on the right hand side of the reaction equation.

For C8H18, the balanced chemical reaction equation for combustion is;

C8H18 + 25/2O2 ----> 8CO2 + 9H2O

Answer:

D

Explanation:

there is no other answer choice that does not move. This is a fool-proof question because all the other answer choices contain movement except the butterfly resting

Answer:

answer is b. : It has been balanced by using the half-reaction method.

Explanation:

edge 2021

Answer:b

Explanation:cuz it is

Answer:1.b 2.A (i think it might be c) 3 (i have no clue) 4.(no clue) Sorry i only got 1 and 2 witch i think are right its been a while sense i have done this....

Explanation:

Answer:

A. Wax drips down the side of a lot candle.

Explanation:

The chemical change from solid to liquid. This is a combustion reaction, so carbon dioxide gas and water vapour is also produced but you can't see them

Answer:

A. Wax drips down the side of a lot candle.

Explanation:

Answer:

the answer would be 6.720

Simply subtract the combined mass by the mass of the beaker.

The answer has 3 decimal places because the least amount of decimal places in the equation is 3.

Answer:

The quantity of  heat required to raise the  temperature of 500 g of  iron by 2°C is 500 J.

Explanation:

Calorimetry is responsible for measuring the amount of heat generated or lost in certain physical or chemical processes.

The sensible heat of a body is the amount of heat received or transferred by a body when undergoing a temperature variation (Δt) without there being a change in physical state (solid, liquid or gaseous).

Its mathematical expression is the fundamental equation of calorimetry. This is:

Q = c * m * ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this  case:

Replacing:

Q= 500 [tex]\frac{J}{kg*C}[/tex] *0.500 kg*2 C

Solving:

Q= 500 J

The quantity of  heat required to raise the  temperature of 500 g of  iron by 2°C is 500 J.

Answer:

66s^-1 will be 1/66

then to convert to minute you multiply by 69

1/66 x 60 = 3960 mins

Answer:

the answer is letter D, Dilute solution

Answer:

aasjajiakjka

Explanation:

Answer:

i think its c [everything is so blury]

Explanation:

Answer:

Explanation:

This is because, Blue color highest frequency of energy after Violet and Indigo.

Answer:

[tex]X=75\%[/tex]

Explanation:

From the question we are told that:

Concentration [tex]C_1=17.50ppb[/tex]

Volume [tex]v=9mL[/tex]

Spike Volume [tex]V_s=1.00mL[/tex]

spike Conc [tex]C_2=2.29 ppb[/tex]

Analysis Conc [tex]C_s=15.93 ppb[/tex]

Generally the equation for  percent recovery is mathematically given by

 [tex]X=\frac{C_s'-C_1'}{C_2'}[/tex]

Where

Concentration of spiked sample C_s'

 [tex]C_s'=C_s*(v+v_s)[/tex]

 [tex]C_s'=15.92*(9+1)[/tex]

 [tex]C_2=159.2[/tex]

Concentration of unspiked sample C_1'

 [tex]C_1'=17.50*9mL[/tex]

 [tex]C_1'=157.5[/tex]

Concentration of spike sample C_2'

 [tex]C_2=2.29*1[/tex]

 [tex]C_2=2.29[/tex]

Therefore

 [tex]X=\frac{159.2-157.5}{2.29}[/tex]

 [tex]X=75\%[/tex]

Answer: The mass of [tex]CO_2[/tex] produced is 0.44 g

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass.  The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of calcium carbonate = 10 g

Molar mass of calcium carbonate = 100 g/mol

Plugging values in equation 1:

[tex]\text{Moles of calcium carbonate}=\frac{10g}{100g/mol}=0.1 mol[/tex]

The formula used to calculate molarity:

[tex]\text{Molarity of solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (mL)}}[/tex] .....(2)

Molarity of HCl = [tex]0.2mol/dm^3=0.2mol/L[/tex]     (Conversion factor: [tex]1L=1dm^3[/tex]

Volume of solution = [tex]100cm^3=100mL[/tex]          (Conversion factor: [tex]1mL=1cm^3[/tex]

Putting values in equation 2, we get:

[tex]0.2=\frac{\text{Moles of HCl}\times 1000}{100}\\\\\text{Moles of HCl}=\frac{0.2\times 100}{1000}=0.02mol[/tex]

For the given chemical reaction:

[tex]CaCO_3(s)+2HCl(aq)\rightarrow CaCl_2(aq)+H_2O(l)+CO_2(g)[/tex]

By stoichiometry of the reaction:

If 2 moles of HCl reacts with 1 mole of calcium carbonate

So, 0.02 moles of HCl will react with = [tex]\frac{1}{2}\times 0.02=0.01mol[/tex] of calcium carbonate

As the given amount of calcium carbonate is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.

Thus, HCl is considered a limiting reagent because it limits the formation of the product.

By the stoichiometry of the reaction:

If 2 moles of [tex]HCl[/tex] produces 1 mole of [tex]CO_2[/tex]

So, 0.02 moles of [tex]HCl[/tex] will produce = [tex]\frac{1}{2}\times 0.02=0.01mol[/tex] of [tex]CO_2[/tex]

We know, molar mass of [tex]CO_2[/tex] = 44 g/mol

Putting values in equation 1, we get:

[tex]\text{Mass of }CO_2=(0.01mol\times 44g/mol)=0.44g[/tex]

Hence, the mass of [tex]CO_2[/tex] produced is 0.44 g

Answer:

1) True

Explanation:

Answer:

The product of an organic reaction is analyzed by column chromatography using silica as the stationary phase and toluene as the mobile phase.

Explanation:

The given statement is true.

In chromatography silica gel is used as the predominant stationary phase.

Since silica gel is a good adsorbent.

It is a polar adsorbent.

In order to remove polar components, silica gel is used as the stationary phase.

Answer is a.true.

Answer:

For A: The wavelength of the light is [tex]1.052\times 10^4nm[/tex]

For B: The number of photons per joule is [tex]2.063\times 10^{18}[/tex]

For C: The binding energy of a metal is 1.197 eV.

Explanation:

The equation used to calculate the energy of a photon follows:

[tex]E=\frac{hc}{\lambda}[/tex]            ......(1)

where,

E = energy of a photon

h = Planck's constant = [tex]6.626\times 10^{-34}J.s[/tex]

c = speed of light = [tex]3\times 10^{8}m/s[/tex]

[tex]\lambda[/tex] = wavelength

Given values:

E = [tex]1.89\times 10^{-20}J[/tex]

Putting values in equation 1, we get:

[tex]\lambda=\frac{(6.626\times 10^{-34}J.s)\times (3\times 10^8m/s)}{1.89\times 10^{-20}J}\\\\\lambda=1.052\times 10^{-5}m[/tex]

Converting the wavelength into nanometers, the conversion factor used is:

[tex]1m=10^9nm[/tex]

So, [tex]\lambda=1.052\times 10^{-5}m\times \frac{10^9nm}{1m}=1.052\times 10^4nm[/tex]

Hence, the wavelength of the light is [tex]1.052\times 10^4nm[/tex]

Given values:

[tex]\lambda=410nm=410\times 10^{-9}m[/tex]

Putting values in equation 1, we get:

[tex]E=\frac{(6.626\times 10^{-34}J.s)\times (3\times 10^8m/s)}{410\times 10^{-9}m}\\\\E=4.848\times 10^{-19}J[/tex]

To calculate the number of photons, we use the equation:

[tex]\text{Number of photons}=\frac{\text{Total energy}}{\text{Energy of a photon}}[/tex]

Total energy = 1 J

Energy of a photon = [tex]4.848\times 10^{-19}J[/tex]

Putting values in the above equation:

[tex]\text{Number of photons}=\frac{1J}{4.848\times 10^{-19}J}\\\\\text{Number of photons}=2.063\times 10^{18}[/tex]

Hence, the number of photons per joule is [tex]2.063\times 10^{18}[/tex]

To calculate the binding energy of a metal, we use the equation:

[tex]E=K+B[/tex]             .....(2)

E = Total energy

K = Kinetic energy of a photon

B = Binding energy of metal

Converting the energy from joules to eV, the conversion factor used is:

[tex]1eV=1.602\times 10^{-19}J[/tex]

Using the above conversion factor:

[tex]K=2.93\times 10^{-19}J=1.829eV\\\\E=4.848\times 10^{-19}J=3.026eV[/tex]

Putting values in equation 2:

[tex]B=(3.026-1.829)eV=1.197eV[/tex]

Hence, the binding energy of a metal is 1.197 eV.