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charle [14.2K]
2 years ago
10

How many electrons does an element have if its atomic number is 20

Chemistry
1 answer:
olga55 [171]2 years ago
6 0

Answer:

20 electrons

A neutral atom with atomic number 20 will have 20 electrons.

The atomic number is, by definiton, the number of protons in an atom's nucleus but for a neutral atom it's also equal to the number of electrons. Each element has a different, unique number of protons that determines its identity.

Explanation:

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Carbon burns in the presence of oxygen to give carbon dioxide. Which chemical equation describes this reaction?
Vlad1618 [11]

Answer: option B.

carbon + oxygen → carbon dioxide

Explanation:

8 0
3 years ago
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Consider the reaction: N2(g) + O2(g) ⇄ 2NO(g) Kc = 0.10 at 2000oC Starting with initial concentrations of 0.040 mol/L of N2 and
IrinaVladis [17]

Answer:

0.011 mol/L

Explanation:

This can be solved with something called an ICE table.

I = initial

C = change

E = equilibrium

Initially, there is 0.04 M of N₂, 0.04 M of O₂, and 0 M of NO.

x amount of N₂ reacts.  Since the stoichiometry is 1:1, x amount of O₂ also reacts.  This produces 2x of NO.

After the reaction, there is 0.04-x of N₂, 0.04-x of O₂, and 2x of NO.

Here it is in table form:

\left[\begin{array}{cccc}&N2&O2&NO\\I&0.04&0.04&0\\C&-x&-x&+2x\\E&0.04-x&0.04-x&2x\end{array}\right]

Now we can use the equilibrium constant:

Kc = [NO]² / ( [N₂] [O₂] )

Substituting:

0.10 = (2x)² / ( (0.04 - x) (0.04 - x) )

Solving:

0.10 = (2x)² / (0.04 - x)²

√0.10 = 2x / (0.04 - x)

(√0.10) (0.04 - x) = 2x

(√0.10)(0.04) - (√0.10)x = 2x

(√0.10)(0.04) = 2x + (√0.10)x

(√0.10)(0.04) = (2 + √0.10)x

x = (√0.10)(0.04) / (2 + √0.10)

x = 0.0055

At equilibrium, the concentration of NO is 2x.  So the answer is:

[NO] = 2x

[NO] = 0.011

The equilibrium concentration of NO is 0.011 mol/L.

3 0
3 years ago
If you were given two transparent liquids how would you determine which is pure and which is salt water
Tpy6a [65]
Based off the salt levels in each water.
8 0
3 years ago
In the combustion of ethane, what is/are the reactant(s)?
aleksley [76]
Reactant are those that combine or reacts to give products !!

so in combustion of ethane ; ethane and o2 are reactants so ... your answer is B !!
5 0
3 years ago
Read 2 more answers
if the percent yield ofr the following reaction is 75% and 45.0g of NO2 are consumed with ercess water in the reaction. how many
NISA [10]

Answer:

30.8 grams of nitric acid are produced

Explanation:

Let's state the reaction:

3 NO₂ + H₂O → 2 HNO₃ + NO

If water is the excess reagent, then the limiting is the gas.

We convert the mass to moles:

45 g . 1 mol/ 46 g = 0.978 moles

Ratio is 3:2. 3 moles of gas can produce 2 moles of acid

Then, 0.978 moles may produce (0.978 . 2) /3 = 0.652 moles of acid

This is the 100% yield, but in this case, the percent yield is 75%

0.652 moles . 0.75 = 0.489 moles

Let's convert the moles to mass → 0.489 mol . 63g / 1mol = 30.8 g

6 0
3 years ago
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