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3 years ago

Describe how is the atomic mass of an atom is calculated.URGENT, NEED TO KNOW NOW!!!

1 answer:

8 0

If it's your first encounter with chemistry, your instructor will want you to learn how to use the periodic table to find the atomic mass (atomic weight) of an element. This number usually is given below an element's symbol. Look for the decimal number, which is a weighted average of the atomic masses of all the natural isotopes of an element.

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Which 3 things are always equal for an atom?

bagirrra123 [75]

Answer:

Atoms always have an equal number of protons and electrons, and the number of protons and neutrons is usually the same as well.

Explanation:

4 0

3 years ago

What is the main cause of earths magnetic field?

love history [14]

The cause of the earths magnetic field is generated from deep down in the core of the earth.

8 0

4 years ago

What is the net ionic equation for the reaction below?

kirill [66]

Answer:

The given reaction in your problem is the ionic equation for an acid (carbonic acid) reacting with a base (sodium hydroxide). All components of the reaction are then written in ionic form except for reactant weak electrolytes and the driving force product compound of the reaction (H2O). See following explanation.

Explanation:

Metathesis Rxn: molecular equation of rxn

H₂CO₃(aq) + 2NaOH(aq) => Na₂CO₃(aq) + 2H₂O(l)

Ionic Equation: shows all components of the reaction

H₂CO₃(aq) + 2Na⁺(aq) + 2OH⁻(aq) => 2Na⁺(aq) + CO₃²⁻(aq) + 2H₂O(l)

H₂CO₃(aq) wk. electrolyte and H₂O(l) driving force compound are not shown ionized in ionic equation. Only strong electrolytes that ionize 100%; i.e., salts and strong acids and bases.

Net Ionic Equation: shows only the reactive components without the spectator ions (nonreactive components), in this case, the Na⁺(aq) ions.

H₂CO₃(aq) + 2OH⁻(aq) => CO₃²⁻(aq) + 2H₂O(l)

3 0

3 years ago

Enter the formula for the compound formed between potassium and sulfur.

Whitepunk [10]

Answer:

K₂S

Explanation:

A chemical formula is a formula showing the symbols of elements present in a compound.

It shows the symbols of the elements in a compound and the number of atoms of each element in the compound.

To write the formula of the compound we need to;

First, identify the elements in the compounds and their symbols

In this case, the symbols of potassium and sulfur are K and S respectively.

Secondly, we need to know their valency.

Potassium has a valency of 1 since it reacts by losing one electron to attain stability while sulfur has a valence of 2 since it reacts by gaining two electrons to attain an octet configuration.

So, we have K¹S²

Thirdly, we write the formula with each element taking the valency of the other element as a subscript.

We get our formula as K₂S.

7 0

3 years ago

A copolymer consisting of vinyl acetate and vinyl chloride has a molar molecular mass of 10 000 g/mol and a degree of polymeriza

Whitepunk [10]

Answer:

C. 0.5

Explanation:

Given that

Molecular mass= 10,000 g/mol

DP= 200

Molecular weight of vinyl chloride = 62.5 g/mol

Molecular weight of vinyl acetate = 86 g/mol

Lets take mole fraction of vinyl chloride is x

And mole fraction of vinyl acetate is (1-x)

As we know that

Mass = number of mole x molecular wight

For vinyl chloride

Mass of vinyl chloride=62.5 x

For vinyl acetate

Mass of vinyl acetate =86(1-x)

Total mass(mass of monomer) = 62.5 x + 86 (1-x) ----1

We know that total weight of polymer given as

total weight of polymer = DP x Mass of monomer

10,000 =200(62.5 x + 86 - 86 x)

23.5 x = 36

x=1.53

This can not be possible .because be assumed that x is less than 1.

If we replace 10,000 by 15,000 then

15,000 =200(62.5 x + 86 - 86 x)

75 =62.5 x + 86 - 86 x

x=0.46

x=0.5

So the answer C is correct.

7 0

3 years ago