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3 years ago

#1: How many valence electrons are in the outermost shell of all halogens?

Chemistry

1 answer:

Kipish [7]3 years ago

3 0

<span>#1: How many valence electrons are in the outermost shell of all halogens?
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How should you add metal to the graduated cylinder so that it will not crack the glass at the bottom?

ella [17]

Answer:

you tilt the cylinder at a slight angle so that the metal slides down the sides, rather than drops all it`s weight to the bottom

5 0

3 years ago

How many atoms are in 2.10 g of K? molar mass of K=39.10g/mole.

Alborosie

Answer:

<h3>The answer is option B</h3>

Explanation:

To calculate the number of atoms we must first calculate the number of moles

Molar mass = mass / number of moles

number of moles = mass / Molar mass

Molar mass (K) = 39.10mole

mass = 2.10g

number of moles = 2.10/ 39.10

= 0.0537mol

After that we use the formula

N = n × L

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10^23 entities

Number of K atoms is

N = 0.0537 × 6.02 × 10^13

<h3>N = 3.23×10^22 atoms of K</h3>

Hope this helps you.

5 0

3 years ago

A 2.912 g sample of a compounds containing only C, H, and O was completely oxidized in a reaction that yielded 3.123 g of water

Taya2010 [7]

Answer:

Explanation:

18 gram of water contains 2 g of hydrogen

3.123 gram of water will contain 2 x 3.123 / 18 = .347 g of hydrogen .

44 gram of carbon dioxide contains 12 g of carbon

7.691 gram of carbon dioxide will contain 12 x 7.691 / 44 = 2.1 g of carbon .

So the sample will contain 2.912 - ( .347 + 2.1 ) g of oxygen .

= .465 g of oxygen .

moles of Carbon = 2.1 / 12 = .175

moles of hydrogen = .347 / 1 = .347

moles of oxygen = .465 / 16 = .029

Ratio of moles of carbon , oxygen and hydrogen ( C,O,H )

= 0.175 : 0.029 : 0.347

= .175/ .029 : 1 : .347 / .029

= 6 : 1 : 12

So empirical formula = C₆H₁₂O

Let the molecular formula be $(C_6H_{12}O)_n$

molecular weight = n ( 6 x 12 + 12x 1 + 16)

= 100 n

Given 100 n = 100.1

n = 1

Molecular formula = C₆H₁₂O.

3 0

3 years ago

20 points please help

exis [7]

The answer should be A, flammability.

The isotopes of the same element would result in the same chemical properties, as the number of protons and electrons are not changed, meanwhile, the physical properties would be slightly different with each other because they have different numbers of electrons.

Out of the 4 options, only option A is a chemical property. Chemical properties are the properties of an element reacting with other substances that creates new substances at the end. While physical properties are the ones that does not produces new substances or any reactions. They are usually observable and measurable.

Therefore, since flammability is a chemical property, the answer is A.

6 0

3 years ago

A mixture of C3H8 and C2H2 has a mass of 2.8 g. It is burned in excess O2 to form a mixture of water and carbon dioxide that con

astraxan [27]

Answer:

The mass of C2H2 in the mixture is 0.56gram using the ratio of carbon in the products contributed by the C2H2.

Explanation:

The balanced equation for the reaction is: C3H8 + 2C2H2 + 10O2 >> 7CO2 + 6H2O.

From the reaction, we know that the oxygen was in excess, this will make the Carbon sources the limiting agents in the reaction. The details of the reaction showed that the ratio of water to the carbon dioxide is 1.6:1. This also means that the expected mole of carbon dioxide will be 7/1.6, which is 3.75moles.

The individual balanced equation of reaction is:

C3H3 +5O2 >> 3CO2 + 4H2O

and 2C2H2 + 5O2 >>4CO2 + 2H2O. From this one can quickly tell that the propane is in sufficient supply as it produces 3 moles of CO2 out of the expected 3.75 moles obtained above. Leaving 0.75moles of CO2 to the ethyne.

The mass of ethyne in the mixture will therefore be: 0.75/3.75 X 2.8 = 0.56g.

4 0

3 years ago