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3 years ago

Which statement describes the periodic table?

Chemistry

2 answers:

Nutka1998 [239]3 years ago

6 0

Periodic table is a scientific model

Leni [432]3 years ago

6 0

Answer;

It is a scientific model.

Explanation;

-A scientific model is a representation of an idea, an object or even a process or a system that is used to describe and explain phenomena that cannot be experienced directly.

-The Periodic Table is an example of a scientific model. It is not only one of the basic organizing principles to which students are introduced, but also a central model used as a tool of induction. Further, the Periodic Table plays a significant role in both understanding of the chemical elements and predicting their features: the elements' structure and properties, and their relationships.

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A compound is found to consist of 34.5% sodium, 16.4% boron, and 48.6% oxygen. What is the empirical formula?

NARA [144]

Answer: The empirical formula is $NaBO_2$

Explanation:

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given:

Mass of Na= 34.5 g

Mass of B= 16.4 g

Mass of O = 48.6 g

Step 1 : convert given masses into moles.

Moles of Na = $\frac{\text{ given mass of Na}}{\text{ molar mass of Na}}= \frac{34.5g}{23g/mole}=1.5moles$

Moles of B = $\frac{\text{ given mass of B}}{\text{ molar mass of B}}= \frac{16.4g}{11g/mole}=1.5moles$

Moles of O = $\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{48.6g}{16g/mole}=3moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For Na = $\frac{1.5}{1.5}=1$

For B = $\frac{1.5}{1.5}=1$

For O = $\frac{3}{1.5}=2$

The ratio of Na: B: O= 1: 1: 2

Hence the empirical formula is $NaBO_2$

7 0

3 years ago

Receiving an electrical shock when you forget to turn off the power before working on an electrical socket is an example of a ne

Sunny_sXe [5.5K]

The answer is false because receiving an electrical shock is not an example of a negative punishment if you forget to turn off the power.

5 0

3 years ago

Read 2 more answers

A science class is conducting an experiment that produces noxious fumes. Because of inadequate ventilation, some students begin

ZanzabumX [31]

Hjkkligfddguiijvgghuhhjjjugtjjjjhhhhhjjjiin do yeah hjkkkjcsduokn 35899&6& cduooookk

4 0

3 years ago

determine the pressure in kpa of hydrogen gas produced when 29.51g of aluminum reacts with excess sodium hydroxide and water if

Mashcka [7]

The pressure of hydrogen gas is 276.25 Kpa .

Given,

Mass of aluminum = 29.51g

Temperature (T) = 25.67 degC =298.67 K

Volume (V) = 14.75 L

The required equation when aluminum reacts with excess sodium hydroxide and water is given by ,

2Al + 2NaOH + 2H2O ==>2NaAlO2 + 3H2

molecular mass of aluminum =26.98 g

1 mole of aluminum= 26.98g

2 moles of aluminum = 53.96g

2 mole of aluminum produces = 3 moles of hydrogen gas

53.96 g of aluminum produces = 6 g of hydrogen gas

29.51 g of aluminum produces = 6*(29.51) /53.96 =3.28 g of hydrogen gas

Thus ,

2 g of hydrogen gas = 1 mole of hydrogen

3.28 g of hydrogen gas = 3.28/2 mole =1.64 mol of hydrogen

Thus , n = 1.64 mol

According to ideal gas equation ,

PV=nRT

P=nRT/V

P = 1.64 * (0.0821L atm K^-1mol^-1 ) *(298.67 K)/14.75L

P=2.726 atm

P= 276.25 Kpa

Hence the pressure of hydrogen gas is 276.25 Kpa .

Learn more about hydrogen gas here :

brainly.com/question/19813237

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3 0

1 year ago

Sodium Tetraborate, a naturally occurring mineral, is crushed into Borax. This is an example of a ________change. *

Ostrovityanka [42]

Answer:

Chemical Change

Explanation:

4 0

3 years ago