What is a molecule that includes the element oxygen?

6. Identify the number of neutrons in one atom of silicon with an isotopic mass number of 28 amu.

Sholpan [36]

14

Explanation:

The number of neutrons in one atom of silicon with an isotopic mass number of 28amu is 14.

An atom is made up three fundamental sub-atomic particles which are:

Protons, neutron and electrons

Protons are the positively charged particles in an atom

Neutrons do not carry any charges

Electrons are the negatively charged particles.

In the nucleus of an atom, both protons and neutrons can be found. They are the massive particle in an atom.

The mass number of an atom = number of protons + number of neutrons

Number of neutrons = mass number - number of protons.

From the periodic table, we know that silicon has an atomic number of 14.

The atomic number is the number of protons in an atom:

Number of neutrons = 28 - 14 = 14amu

In the atom, we will have 14amu of neutrons in a silicon atom.

learn more:

Number of neutrons brainly.com/question/2757829

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5 0

4 years ago

All exothermic reactions _____. Select all that apply. a. are endothermic b. are exothermic c.release energy d.are rapid reactio

Paha777 [63]

Answer:

All exothermic reactions _c.release energy____

Explanation:

Exothermic reactions are those that give off energy, for example in the form of heat in combustion (it has a negative enthalpy variation, the energy of the products being less than the energy of the reagents)

4 0

3 years ago

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What does group 16 (oxygen family) have in common

Dimas [21]

Answer: here is your answer

Explanation:

The oxygen family consists of the elements that make up group 16 on the periodic table: oxygen, sulfur, selenium, tellurium, and polonium. These elements all have six electrons in their outermost energy level, accounting for some common chemical properties among them.

7 0

3 years ago

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Please help with #2 and #3

Vaselesa [24]

Answer:

2. $V_2=17L$

3. $V=82.9L$

Explanation:

Hello there!

2. In this case, we can evidence the problem by which volume and temperature are involved, so the Charles' law is applied to:

$\frac{V_2}{T_2}=\frac{V_1}{T_1}$

Thus, considering the temperatures in kelvins and solving for the final volume, V2, we obtain:

$V_2=\frac{V_1T_2}{T_1}$

Therefore, we plug in the given data to obtain:

$V_2=\frac{18.2L(22+273)K}{(45+273)K} \\\\V_2=17L$

3. In this case, it is possible to realize that the 3.7 moles of neon gas are at 273 K and 1 atm according to the STP conditions; in such a way, considering the ideal gas law (PV=nRT), we can solve for the volume as shown below:

$V=\frac{nRT}{P}$

Therefore, we plug in the data to obtain:

$V=\frac{3.7mol*0.08206\frac{atm*L}{mol*K}*273.15K}{1atm}\\\\V=82.9L$

Best regards!

6 0

3 years ago

During chemistry, Dan mixes two clear, colorless solution and mixing them produces a yellow precipitate in a clear, colorless fi

kondor19780726 [428]

Answer : Formation of yellow precipitate is the physical evidence that there has been a chemical reaction.

Explanation :

A chemical reaction happens when 2 or more substances chemically react with each other.

There are 4 evidences indicating that a chemical reaction has occurred which are mentioned below.

1. Change in color : On mixing, the reaction mixture can change color indicating that a chemical change may have occurred.

2. Formation of precipitate : A reaction in which a solid is formed on mixing 2 aqueous solutions is called as precipitation reaction. Here, the formation of solid indicates a chemical change.

ex. $AgNO_{3} (aq) + NaCl (aq) \rightarrow AgCl (s) + NaNO_{3} (aq)$

In above reaction, on mixing the solutions, a white precipitate of AgCl is formed which indicates a chemical change.

3. Evolution of gas : A chemical change also occurs when a gas is evolved on mixing 2 substances.

ex. $2HCl (aq) + Na_{2}CO_{3} (aq) \rightarrow 2NaCl (aq) + H_{2}O (l) + CO_{2} (g)$

In above reaction, CO2 gas is evolved and bubbles can be seen in the form of effervescence.

4. Change in temperature : Certain chemical reactions absorb or evolve heat. When a chemical reaction evolves heat, the temperature of the final reaction mixture increases and when it absorbs heat, the temperature decreases. This increase and decrease in temperature indicates a chemical change.

ex. $HCl (aq) + NaOH (aq) \rightarrow NaCl(aq) + H_{2}O (l)$

In above reaction, the final mixture becomes hot as the reaction releases heat. ( Exothermic)

Change in odor also indicates a chemical change.

For the given reaction, a yellow precipitate of PbI2 is getting formed.

Therefore formation of this precipitate is the physical evidence that there has been a chemical reaction.

8 0

3 years ago