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max2010maxim [7]
3 years ago
15

Why are relative atomic masses on the periodic tables not whole numbers?

Chemistry
2 answers:
Kobotan [32]3 years ago
6 0

Answer:

They are averages.

Explanation:

atomic numbers on periodic tables are derived from the average value of all the isotopes of the element. So being averages they are sometimes not integers.

Darya [45]3 years ago
4 0

Answer:

The sum of the number of protons and neutrons in an atom is called the mass number.  Atomic mass is never an integer number for several reasons: The atomic mass reported on a periodic table is the weighted average of all the naturally occurring isotopes. Being an average it would be most unlikely to be a whole number.

Explanation:

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What is the volume of 1.56 kg of a compound whose molar mass is 81.86 g/mole and whose density is 41.2 g/ml?
hjlf

Answer:

v = 37.9 ml

Explanation:

Given data:

Mass of compound = 1.56 kg

Density = 41.2 g/ml

Volume of compound = ?

Solution:

First of all we will convert the mass into g.

1.56 ×1000 = 1560 g

Formula:

D=m/v

D= density

m=mass

V=volume

v = m/d

v =  1560 g / 41.2 g/ml

v = 37.9 ml

7 0
3 years ago
A large cyclotron directs a beam of He++ nuclei onto a target with a beam current of 0.250 mA. (a) How many He++ nuclei per seco
nikitadnepr [17]

Answer:

a. 7.8*10¹⁴ He⁺⁺ nuclei/s

b. 4000s

c. 7.7*10⁸s

Explanation:

I = 0.250mA = 2.5 * 10⁻³A

Q = 1.0C

1 e- contains 1.60 * 10⁻¹⁹C

But He⁺⁺ Carrie's 2 charge = 2 * 1.60*10⁻¹⁹C = 3.20*10⁻¹⁹C

(A).

No. Of charge per second = current passing through / charge

1 He⁺⁺ = 2.50 * 10⁻⁴ / 3.2*10⁻¹⁹C

1 He⁺⁺ = 7.8 * 10¹⁴ He⁺⁺ nuclei

(B).

I = Q / t

From this equation, we can determine the time it takes to transfer 1.0C

I = 1.0 / 2.5*10⁻⁴ = 4000s

(C).

Time it takes for 1 mol of He⁺⁺ to strike the target =?

Using Avogadro's ratio,

1.0 mole of He = (6.02 * 10²³ ions/mol ) * (1 / 7.81*10¹⁴ He ions)

Note : ions cancel out leaving the value of the answer in mols.

1.0 mol of He = 7.7 * 10⁸s

8 0
3 years ago
Which answer best explains the relationship between size and mass of the sun?
gizmo_the_mogwai [7]
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3 0
3 years ago
The image shows a molecular model of a compound using balls and sticks. Each ball is an atom and each stick is a bond. If you we
Zielflug [23.3K]
Hi , the answers must be part B
3 0
3 years ago
Read 2 more answers
Li + HNO3 > LiNO3 + H2 how do I balance it? Show work pls
azamat

Answer: The balanced equation is 2Li + 2HNO_{3} \rightarrow 2LiNO_{3} + H_{2}.

Explanation:

The given reaction equation is as follows.

Li + HNO_{3} \rightarrow LiNO_{3} + H_{2}

Number of atoms present on reactant side are as follows.

  • Li = 1
  • H = 1
  • NO_{3} = 1

Number of atoms present on product side are as follows.

  • Li = 1
  • H = 2
  • NO_{3} = 1

To balance this equation, multiply Li by 2 and HNO_{3} by 2 on reactant side. Also, multiply LiNO_{3} by 2 on product side.

Hence, the equation can be rewritten as follows.

2Li + 2HNO_{3} \rightarrow 2LiNO_{3} + H_{2}

Now, number of atoms present on reactant side are as follows.

  • Li = 2
  • H = 2
  • NO_{3} = 2

Number of atoms present on product side are as follows.

  • Li = 2
  • H = 2
  • NO_{3} = 2

As there are same number of atoms on both reactant and product side. Hence, the equation is now balanced.

Thus, we can conclude that the balanced equation is 2Li + 2HNO_{3} \rightarrow 2LiNO_{3} + H_{2}.

3 0
2 years ago
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