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3 years ago

Which element has 2 valence electrons and is in period 4?

1 answer:

6 0

The correct answer is calcium. We know this because if we look at the periodic table calcium is the only option in period 4.

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Dimethyl sulfoxide [(ch3)2so], also called dmso, is an important solvent that penetrates the skin, enabling it to be used as a t

Bas_tet [7]

The molecular formula of dimethyl sulfoxide is $(CH_{3})_{2}SO$ . Molar mass of dimethyl sulfoxide is 78.13 g/mol. Calculate number of moles as follows:

$n=\frac{m}{M}=\frac{7.14\times 10^{3} g}{78.13 g/mol}=91.38 mol$

From the molecular formula, 1 mole of dimethyl sulfoxide contains 2 moles of Carbon, 6 moles of Hydrogen, 1 mole of Sulfur and 1 mole of oxygen.

Thus, 91.38 moles of dimethyl sulfoxide will have:

Carbon :

$n_{C}=2\times 91.38 moles=182.77 moles$

Hydrogen:

$n_{H}=6\times 91.38 moles=548.28 moles$

Sulfur:

$n_{S}=1\times 91.38 moles=91.38 moles$

Oxygen:

$n_{O}=1\times 91.38 moles=91.38 moles$

Since, 1 mole of an element equals to $6.023\times 10^{23}$ atoms thus, number of atoms can be calculated as:

Carbon:

$1 mole\rightarrow 6.023\times 10^{23} atoms$

Thus,

$182.77 moles\rightarrow 182.77\times 6.023\times 10^{23} atoms=1.10\times 10^{26} atoms$

Hydrogen:

$1 mole\rightarrow 6.023\times 10^{23} atoms$

Thus,

$548.28 moles\rightarrow 548.28\times 6.023\times 10^{23} atoms=3.30\times 10^{26} atoms$

Sulfur:

$1 mole\rightarrow 6.023\times 10^{23} atoms$

Thus,

$91.38 moles\rightarrow 91.38\times 6.023\times 10^{23} atoms=5.50\times 10^{25} atoms$

Oxygen:

$1 mole\rightarrow 6.023\times 10^{23} atoms$

Thus,

$91.38 moles\rightarrow 91.38\times 6.023\times 10^{23} atoms=5.50\times 10^{25} atoms$

Therefore, number of C, S, H and O atoms are $1.10\times 10^{26}, 5.50\times 10^{25}, 3.30\times 10^{26} and 5.50\times 10^{25} atoms$ respectively.

4 0

4 years ago

Can you guys help me :) ?<br>winner takes all

posledela

Answer:

1. Ag2CO3

2.Ba3(PO4)2

3. Cu(OH)2

4. AL

Explanation:

5 0

3 years ago

The reaction A+B-> C+D rate=k[A][B]^2 has an initial rate of 0.0810 M/s. What will the initial rate be if [A] is halved and [

makkiz [27]

The first to do is to isolate the constant, k, to one side. The rate expression would then be:

k = rate/ <span>[A][B]^2

This constant, k, will be the same for the given reaction at a certain temperature. Then, we can relate a second rate to this reaction.

</span>rate1/ [A1][B1]^2 = rate2/ [A2][B2]^2

First question:
0.0810 / [A1][B1]^2 = rate2/ <span>[A2/2][3B2]^2
rate2 = (</span>0.0810 [A2/2][3B2]^2 )/ [A1][B1]^2
rate2 = 0.3645 M/s

Second Equation:
0.0810 / [A1][B1]^2 = rate2/ <span>[A2/2][3B2]^2
rate2 = (</span>0.0810 [3A2][B2/2]^2 )/ [A1][B1]^2
<span>rate2 = 0.0608 M/s</span>

3 0

3 years ago

Identify the molecule with the highest boiling point. C 6H 6 NH 3 OF 2 CHCl 3

lakkis [162]

Answer:

Option NH 3 is the correct answer.

Explanation:

A molecule which has hydrogen bonding will have the highest boiling point. So, out of the given options only NH 3 will have hydrogen bonding.

Whereas in CHCI 3 there will be dipole-dipole interactions and no hydrogen bonding within the molecule.

In OF 2 and C 6H 6, there will be dipole-dipole interaction in both the molecules.

Thus, we can conclude that NH 3 will have the highest boiling point.

7 0

4 years ago

Identify each definition that applies to the compound in red. Check all that apply. Upper F superscript minus in red plus upper

likoan [24]

The fluoride ion in the reaction has been the acceptor of the hydrogen. Thus, the fluoride ion has been the Brønsted Lowry base.

<h3 /><h3>What is the Brønsted Lowry acid and base concept?</h3>

The Brønsted Lowry acid and base concept can be described based on the proton acceptor and donor. The Brønsted Lowry acid has been the proton donor, and the Brønsted Lowry base has been the proton acceptor.

The Arrhenius concept is based on hydrogen and hydroxide donors. The Arrhenius base has been the hydroxide donor, and the Arrhenius acid has been the hydrogen donor.

Since the fluoride ion has been the proton acceptor in the reaction, it has been the Brønsted Lowry base.

Lear more about Brønsted Lowry acid and base, here:

brainly.com/question/21736327

4 0

2 years ago