Ask question

Ask question

All categories

3 years ago

13

an unknown element has an atomic number of 6 and an atomic mass of 13 .based on this information what is the identity of this un

known element

1 answer:

makkiz [27]3 years ago

8 0

So if you look through the periodic table you can see that the element is Carbon(symbol C)

You might be interested in

A power plant is driven by the combustion of a complex fossil fuel having the formula C11H7S. Assume the air supply is composed

AlekseyPX

(a) 4C_11 H_7S + 55O_2 → 44CO_2 + 14H_2O + 4SO_2 + 20.68N_2;

(b) 4C_11 H_7S + 66O_2 → 44CO_2 + 14H_2O + 4SO_2 + 248.2N_2 + 11O_2;

(c) 23 900 kg air; (d) air:fuel = 10.2; (e) air:fuel = 12.2:1

(a) <em>Balanced equation including N_2 from air</em>

The balanced equation <em>ignoring</em> N_2 from air is

4C_11 H_7S + 55O_2 → 44CO_2 + 14H_2O + 4SO_2

Moles of N_2 =55 mol O_2 × (3.76 mol N_2/1 mol O_2) = 206.8 mol N_2

<em>Including</em> N_2 from air, the balanced equation is

4C_11 H_7S + 55O_2 → 44CO_2 + 14H_2O + 4SO_2 + 206.8N_2

(b) <em>Balanced equation for 120 % stoichiometric combustion</em>

Moles of O_2 = 55 mol O_2 × 1.20 = 66.00 mol O_2

Excess moles O_2 = (66.00 – 55) mol O_2 = 11.00 mol O_2

Moles of N_2 = 66.00 mol O_2 × (3.76 mol N_2/1 mol O_2) = 248.2 mol N_2

The balanced equation is

4C_11 H_7S + 66O_2 → 44CO_2 + 14H_2O + 4SO_2 + 248.2N_2 + 11O_2

(c) <em>Minimum mass of air</em>

Moles of O_2 required = 1700 kg C_11 H_7S

× (1 kmol C_11 H_7S/185.24 kg C_11 H_7S) × (55 kmol O_2/4 kmol C_11 H_7S)

= 126.2 kmol O_2

Mass of O_2 = 126.2 kmol O_2 × (32.00 kg O_2/1 kmol O_2) = 4038 kg O_2

Mass of N_2 required = 126.2 kmol O_2 × (3.76 kmol N_2/1 kmol O_2)

× (28.01 kg N_2/1 kmol N_2) = 13 285 kg N_2

Mass of air = Mass of N_2 + mass of O_2 = (4038 + 13 285) kg = 17 300 kg air

(d) <em>Air:fuel mass ratio for 100 % combustion</em>

Air:fuel = 17 300 kg/1700 kg = <em>10.2 :1 </em>

(e) <em>Air:fuel mass ratio for 120 % combustion </em>

Mass of air = 17 300 kg × 1.20 = 20 760 kg air

Air:fuel = 20 760 kg/1700 kg = 12.2 :1

6 0

3 years ago

25cm3 of gas at 1 atm has a temperature of 20 degree celsis .

Andreas93 [3]

Answer:

1.28 atm

Explanation:

To solve this problem, you need to use the gas laws, more specifically the Combined Gas Law. It is P1V1/T1 = P2V2/T2. Simply plug your values in. But be careful! Make sure you convert your 20 degree C and 28 deg C to Kelvin, as that it the only temperature scale the Gas Laws work with. Upon plugging in your values, you get approximately 1.28 atm.

6 0

3 years ago

Is trimming a bush because it grows too tall a chemical or physical change

professor190 [17]

Answer:

Physical Change

Explanation:

The bush is changing shapes, not changing what it is.

8 0

4 years ago

HClO4 acid solution has a concentration of 5 Molarity. Calculate the concentration of this solution in

Nutka1998 [239]

Answer:

1. Percentage by weight = 0.5023 = 50.23 %

2. molar fraction =0.153

Explanation:

We know that

Molar mass of HClO4 = 100.46 g/mol

So the mass of 5 Moles= 5 x 100.46

Mass (m)= 5 x 100.46 = 502.3 g

Lets assume that aqueous solution of HClO4 and the density of solution is equal to density of water.

Given that concentration HClO4 is 5 M it means that it have 5 moles of HClO4 in 1000 ml.

We know that

Mass = density x volume

Mass of 1000 ml solution = 1 x 1000 =1000 ( density = 1 gm/ml)

m'=1000 g

1.

Percentage by weight = 502.3 /1000

Percentage by weight = 0.5023 = 50.23 %

2.

We know that

molar mass of water = 18 g/mol

mass of water in 1000 ml = 1000 - 502.3 g=497.9 g

So moles of water = 497.7 /18 mole

moles of water = 27.65 moles

So molar fraction = 5/(5+27.65)

molar fraction =0.153

6 0

3 years ago

Calculate the Molecular or Formula massof each of the following:

DiKsa [7]

Explanation:

Molar mass

The mass present in one mole of a specific species .

The molar mass of a compound , can easily be calculated as the sum of the all the individual atom multiplied by the number of total atoms .

(a) P₄

Molar mass of of the atoms are -

Phosphorous , P = 31 g/mol

Molecular mass of P₄ = ( 4 * 31 ) = 124 g/mol .

(b) H₂O

Molar mass of of the atoms are -

Hydrogen , H = 1 g/mol

oxygen , O = 16 g/mol.

Molecular mass of H₂O = ( 2 * 1 ) + ( 1 * 16 ) = 18 g/mol

(c) Ca(NO₃)₂

Molar mass of of the atoms are -

calcium , Ca = 40 g/mol

nitrogen, N = 14 g/mol

oxygen , O = 16 g/mol.

Molecular mass of Ca(NO₃)₂ = ( 1 * 40 ) + ( 2 * 14 ) + ( 6 * 16 ) = 164 g/mol.

(d)CH₃CO₂H (acetic acid)

Molar mass of of the atoms are -

Carbon , C = 12 g/mol.

oxygen , O = 16 g/mol.

Hydrogen , H = 1 g/mol

Molecular mass of CH₃CO₂H =( 2 * 12 ) + (2 * 16 ) + (4 * 1 ) = 60 g/mol.

(e) C₁₂H₂₂O₁₁ (sucrose, cane sugar).

Molar mass of of the atoms are -

Carbon , C = 12 g/mol.

oxygen , O = 16 g/mol.

Hydrogen , H = 1 g/mol

Molecular mass of C₁₂H₂₂O₁₁ = (12 * 12 ) + ( 22 * 1 ) + ( 11 * 16 ) = 342 g/mol.

4 0

3 years ago