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marishachu [46]
2 years ago
5

James was given a sample of sodium bicarbonate NaHCO3 in a weighing dish to analyze. His teacher asked him to find the percent o

f each element in the compound. He easily calculated the first three elements, but was stumped when he got to oxygen. What is the percent oxygen in the compound? Round to the nearest whole number.
Chemistry
2 answers:
svetlana [45]2 years ago
7 0

Answer:

57.14 % ≈ 57 %

Explanation:

First step is to find the molar mass of the compound. This is done by adding the atomic masses of the elements present.

The atomic masses of the elements are given below;

Na = 22.99 g/mol

H = 1.01 g/mol

C = 12.01 g/mol

O = 16.00 g/mol

NaHCO3 = (1 mol * Na) + (1 mol * H) + ( 1 mol * C) + (3 mol * O)

NaHCO3 = (1 * 22.99) + (1 * 1.01) + (1 * 12.01) + (3 * 16)

NaHCO3 = 22.99 + 1.01 + 12.01 + 48

NaHCO3 = 84.01g

Formular for percentage composition;

Percentage composition = (Mass of element / Mass of Compound) * 100

Percentage composition = (48 / 84.01) * 100

Percentage composition = 57.14 %

Rounding up to the nearest whole number = 57 %

gtnhenbr [62]2 years ago
5 0
This question could be answered easily if the results of the abundance of the other elements are given. You will just have to subtract the sum of all their abundances to 100. Since it's not given, the solution would just be:

Na = 23 g/mol* 1 = 23 g
H = 1 g/mol * 1 = 1 g
C = 12 g/mol * 1 = 12 g
O = 16 g/mol * 3 = 48 g
Total = 84 g

% O = 48/84 * 100 = <em>57.14%</em>

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Two students are working together to build two models. Both models will represent the molecular structure of sodium bicarbonate,
vfiekz [6]

Answer:

Altogether for both models; two red jellybeans, two white jellybeans, two black jellybeans and six blue jellybeans.

<em>Note: Since no specific color was stated for oxygen atoms, the answer assigns blue colored jellybeans to represent oxygen atoms.J</em>

Explanation:

Sodium bicarbonate, NaHCO₃ is a compound composed of one atom of sodium, one atom of hydrogen, one atom of carbon and three atoms of oxygen.

Since red jellybeans represent sodium atoms, white jellybeans represent hydrogen atoms, black jellybeans represent carbon atoms and blue jellybeans represent oxygen atoms, each of the two students will require the following number of each jellybean for their model of sodium carbonate: One red jellybean, one white jellybean, one black jellybean and three blue jellybeans.

Altogether for both models; two red jellybeans, two white jellybeans, two black jellybeans and six blue jellybeans.

8 0
2 years ago
A certain radioactive atom has 90 protons and 142 neutrons. If this atom undergoes alpha decay, what is the mass number of the d
Hatshy [7]

Answer: the mass number of the daugther atom is 232,


Explanation:


1) Alpha (α) decay is a nuclear reaction in which a nucleus (parent's nucleus) emits an alpha (α) particle and leads to a different atom (daughter atom).


2) The alpha (α) particle is a nucleus of helium atom, i,e, a nucleus with two protons and two neutrons. The symbol used for the α particles is <em>⁴₂He</em>, where the superscript 4 indicates the mass number (2 protons + 2 neutrons = mass number 4), and the subscript 2 indicates the atomic number (number of protons).


3) Then, to determine the mass number of the daughter atom you just need to do a mass number balance:


mass number of the parent atom = mass number of the daugther atom + mass number of the α particle.


The mass number of the radioactive (parent) atom is 90 protons + 142 neutrons = 232.


∴ 232 = x + 4 ⇒ x = 232 - 4 = 228 ← answer.


The full equation may help you to have a wider vision of the problem:


²³²₉₀ X → ⁴₂ He + ²²⁸₈₈ Y

Note this:

  • 232 = 4 + 228 (this is a mass number balance)
  • 90 = 2 + 88 (this is an atomic number balance)
  • X is the parent atom, and Y is the daughter atom
  • You can use a periodic table to determine the identity of the unknown atoms (using the atomic numbers).
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2 years ago
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vesna_86 [32]

First situation:

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Reika [66]
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Answer:

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1.)azeotrope is a mixture of two or more liquid components under constant boiling, it has a constant mole fraction composition of present component which can be homogeneous or heterogeneous.

2.)the condition which it's best performed when there's liquids that is non-volatile which boils higher than other liquids with at least 26 degrees .

steam azentropic distillation

3.During a steam distillation, How to know if the organic compound is still coming over is when you see the solution becoming cloudy or when there is existence of two layers.

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A.) Layers that are mostly water H2O

B.) Layers that are mostly products

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