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lorasvet [3.4K]
3 years ago
9

Which scientist arranged the elements in order of increasing atomic number, rather than increasing atomic mass? Antoine Lavoisie

r Dmitri Mendeleev Henry Moseley John Newlands
Chemistry
2 answers:
Natalka [10]3 years ago
6 0
The answer is Henry Moseley
Luba_88 [7]3 years ago
4 0

The answer is: Henry Moseley.

Henry Gwyn Jeffreys Moseley (1887–1915) proposed that the number of positive nuclear charges (protons) in atom is equal to its atomic number in the periodic table.

Mendeleev did not know about isotopes and he arranged the elements in order of increasing relative atomic mass.

For example, positions of iodine and tellurium were reversed in Mendeleev's table, because of different isotopes, but Moseley solved anomalies like this one.

You might be interested in
11.9 g Cl2 is reacted with 10.7 g NaOH. How many moles of NaCl are produced?
melisa1 [442]

Answer:

1. 7.256g of NaCl

2. 47.33g of Cl2

Explanation:

2 moles of Na reacts to produce 2 moles of NaCl

8 moles of Na will still produce 8 moles of NaCl

Mass of NaCl = molar mass of Nacl/moles of Nacl

=58.5/8

=7.256g of NaCl

From the equation, 2 moles of Na reacts with 1 mole of Cl2

3/2 moles of Cl2 will react with 3 moles of Na

Mass of Cl2 = 71/1.5

=47.33g of Cl2

Explanation:

4 0
3 years ago
Thermal energy is transferred from?
aliina [53]

Answer:

chemical and electrical ( and sometimes nucelar)

Explanation:

4 0
3 years ago
Read 2 more answers
How fast is the speed of light?
Tpy6a [65]

The speed of light is 299,792,458 meters per second in vacuum.
It's somewhat slower in any material substance, and different in
each substance.

(That's 186,282.4  miles per second.)


7 0
3 years ago
A mixture of helium and methane gases, at a total pressure of 821 mm Hg, contains 0.723 grams of helium and 3.43 grams of methan
Nookie1986 [14]

<u>Answer:</u>

<u>For 1:</u> The partial pressure of helium is 376 mmHg and that of methane gas is 445 mmHg

<u>For 2:</u> The mole fraction of nitrogen gas is 0.392 and that of carbon dioxide gas is 0.608

<u>Explanation:</u>

<u>For 1:</u>

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

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

  • <u>For helium:</u>

Given mass of helium = 0.723 g

Molar mass of helium = 4 g/mol

Putting values in equation 1, we get:

\text{Moles of helium}=\frac{0.723g}{4g/mol}=0.181mol

  • <u>For methane gas:</u>

Given mass of methane gas = 3.43 g

Molar mass of methane gas = 16 g/mol

Putting values in equation 1, we get:

\text{Moles of methane gas}=\frac{3.43g}{16g/mol}=0.214mol

To calculate the mole fraction , we use the equation:

\chi_A=\frac{n_A}{n_A+n_B}     .......(2)

To calculate the partial pressure of gas, we use the equation given by Raoult's law, which is:

p_{A}=p_T\times \chi_{A}       ......(3)

  • <u>For Helium gas:</u>

We are given:

n_{He}=0.181mol\\n_{CH_4}=0.214mol

Putting values in equation 2, we get:

\chi_{He}=\frac{0.181}{0.181+0.214}=0.458

Calculating the partial pressure by using equation 3, we get:

p_T=821mmHg\\\\\chi_{He}=0.458

Putting values in equation 3, we get:

p_{He}=0.458\times 821mmHg=376mmHg

  • <u>For Methane gas:</u>

We are given:

n_{He}=0.181mol\\n_{CH_4}=0.214mol

Putting values in equation 2, we get:

\chi_{CH_4}=\frac{0.214}{0.181+0.214}=0.542

Calculating the partial pressure by using equation 3, we get:

p_T=821mmHg\\\\\chi_{CH_4}=0.542

Putting values in equation 3, we get:

p_{CH_4}=0.542\times 821mmHg=445mmHg

Hence, the partial pressure of helium is 376 mmHg and that of methane gas is 445 mmHg

  • <u>For 2:</u>

We are given:

Partial pressure of nitrogen gas = 363 mmHg

Partial pressure of carbon dioxide gas = 564 mmHg

Total pressure = (363 + 564) mmHg = 927 mmHg

Calculating the mole fraction of the gases by using equation 3:

<u>For nitrogen gas:</u>

363=\chi_{N_2}\times 927\\\\\chi_{N_2}=\frac{363}{927}=0.392

<u>For carbon dioxide gas:</u>

564=\chi_{CO_2}\times 927\\\\\chi_{CO_2}=\frac{564}{927}=0.608

Hence, the mole fraction of nitrogen gas is 0.392 and that of carbon dioxide gas is 0.608

6 0
3 years ago
Consider a sample of a hydrocarbon (a compound consisting of only carbon and hydrogen) at 0.959 atm and 298 K. Upon combusting t
Masja [62]

Answer:

Molecular formula of hydrocarbon is: C₂H₆

Explanation:

The combusting of the hydrocarbon:

CxHy + O₂ → CO₂ + H₂O

Using gas law to obtain molar mass of the gas mixture (CO₂ + H₂O):

P/RT = n/V

Where:

P is pressure (1,208 atm)

R is gas constant (0,082 atmL/molK)

T is temperature (375 K)

n/V = 0,0393 mol/L

1,1128 g/L ÷ 0,0393 mol/L = 28,32 g/mol

Thus, average molecular weight is:

28,32 g/mol = 44,01 g/mol X + 18,02 g/mol Y

1 = X + Y

Where X is CO₂ molar percentage and Y is H₂O molar percentage.

Solving:

X = 0,397

Y = 0,603

39,7% H₂O

60,3% CO₂

With this proportion you can obtain ratio CO₂:H₂O thus:

60,3/39,7 = 1,52 So, 2 CO₂: 3H₂O

The moles of the hydrocarbon are:

PV/RT = n

P (0,959 atm)

V ( 1/5 of final volume)

T (298K)

n = 7,85x10⁻³ mol

The moles of CO₂ are:

0,0393 mol × 2 mol CO₂/ 5 mol total =0,01572.

Ratio of CO₂:CxHY =

0,01572 : 7,85x10⁻³ 2 CO₂: 1 CxHY

Doing:

1 CxHy + O₂ → 2 CO₂ + 3 H₂O

By mass balance:

1 C₂H₆ + 7/2 O₂  → 2 CO₂ + 3 H₂O

Thus, molecular formula of hydrocarbon is: <em>C₂H₆ </em>

I hope it helps!

7 0
3 years ago
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