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andrew-mc [135]
2 years ago
11

Why are there only two elements in the first period of the periodic table?

Chemistry
2 answers:
noname [10]2 years ago
8 0
The reason why there are only two elements in the first period of the periodic table is because hydrogen is the main reactant while helium is the main non-reactant.
Solnce55 [7]2 years ago
5 0
The first period has less elementsthan any other periods in the periodic table. There are only two elements in the first period: hydrogen and helium. We can explain why there is lesselements in the first row in modern theories of atomic structure. ... Theseelements can only hold two electrons, both in the 1s orbital
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The total pressure of a confined mixture of gases is the sum of the pressures of each of the gases in the mixture. This is known
olganol [36]

Answer:

D

Explanation:

It is also known as the Dalton’s law of partial pressure. Given a confinement that contains a mixture of gases which do not mix, the total pressure equals the sum of the individual pressures.

The term, which do not mix is necessary because, if the gases are the type that mix, the law will no longer hold as they would have given up their individual identities and hence their individual partial pressure cannot be use to access them anymore.

Hence, the law helps to sum the totality of the pressures of a number of gases which exists together in a confinement and they do not mix. Say we have 3 gases A, B and C. The total pressure is the sum of pressure A, pressure B and pressure C.

5 0
3 years ago
The following equation is balanced correctly. 4C2H6 + 7O2 --&gt; 6H2O + 4CO2<br> True <br> False
Ostrovityanka [42]

Answer: False

Explanation:

4C2H6 + 7O2 --> 6H2O + 4CO2

8 Carbons on the reactant side, but 4 Carbons on the Product

24 Hydrogens on Reactant, 12 H on product

But Oxygen is balanced, 14 on each side

4 0
3 years ago
Read 2 more answers
Name the parts of an electromagnet
Oxana [17]

Answer:

The iron core, copper wire, and an electricity source.

Explanation: Me

7 0
3 years ago
What is equal to the number of particles in 36 grams of carbon-12?
HACTEHA [7]

Answer:

3 moles

Explanation:

To solve this problem we will  use the Avogadro numbers.

The number 6.022×10²³ is called Avogadro number and it is the number of atoms, ions or molecules in one mole of substance.  According to this,

1.008 g of hydrogen = 1 mole =  6.022×10²³  atoms.

18 g water = 1 mole = 6.022×10²³ molecules

we are given 36 g of C-12. So,

12 g of C-12 = 1 mole

24 g of C-12 =  2 mole

36 g of C-12 = 3 mole

So 3 moles of C-12 equals to the number of particles in 36 g of C-12.

4 0
2 years ago
Consider the reaction: 2 H2O (g)--&gt;2 H2 (g) + O2 (g). ΔH=483.6 Kj/mol. If 2 moles of H2O (g) are converted H2(g) and O2(g) ag
denis-greek [22]
DE = dH - PdV 

<span>2 H2O(g) → 2 H2(g) + O2(g) </span>

<span>You can see that there are 2 moles of gas in the reactants and 3 moles of gas in the products. </span>

<span>1 moles of ideal gas occupies the same volume as 1 mole of any other ideal gas under the same conditions of temp and pressure. </span>

<span>Since it is done under constant temp and pressure that means the volume change will be equal to the volume of 1 mole of gas </span>

<span>2 moles reacts to form 3 moles </span>

<span>The gas equation is </span>

<span>PV = nRT </span>
<span>P = pressure </span>
<span>V = volume (unknown) </span>
<span>n = moles (1) </span>
<span>R = gas constant = 8.314 J K^-1 mol^-1 </span>
<span>- the gas constant is different for different units of temp and pressure (see wikki link) in this case temp and pressure are constant, and we want to put the result in an equation that has Joules in it, so we select 8.314 JK^-1mol^-1) </span>
<span>T = temp in Kelvin (kelvin = deg C + 273.15 </span>
<span>So T = 403.15 K </span>

<span>Now, you can see that PV is on one side of the equation, and we are looking to put PdV in our dE equation. So we can say </span>

<span>dE = dH -dnRT (because PV = nRT) </span>

<span>Also, since the gas constant is in the unit of Joules, we need to convert dH to Joules </span>

<span>dH = 483.6 kJ/mol = 483600 Joules/mol </span>

<span>dE = 483600 J/mol - (1.0 mol x 8.314 J mol^-1K-1 x 403.15 K) </span>
<span>dE = 483600 J/mol - 3351.77 J </span>
<span>dE = 480248.23 J/mol </span>
<span>dE = 480.2 kJ/mol </span>
5 0
3 years ago
Read 2 more answers
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