If the statement is true, select True. If it is false, select False.

In a physical change, some of the physical properties of the substance may be altered and the chemical composition remains the same.

True
False

Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

[tex]volume = \frac{mass}{density} \\[/tex]

From the question we have

[tex]volume = \frac{78}{7.8} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

It is 34

Explanation:

The atom that has 24 protons, 22 electrons, and 28 neutrons has an atomic number of 24.

ATOMIC NUMBER:

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Answer:

It only has 7 valence electrons because there are seven electrons in the highest orbital.

Explanation:

Answer:

ooooooooooooooooooh i dont know this one

Explanation:

im not good a math at all

Answer:

A

Explanation:

Answer: The final volume of the balloon is 335.6 L

Explanation:

To calculate the final volume of the balloon, we use the equation given by combined gas law:

[tex]\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]

where,

[tex]P_1[/tex] = Initial pressure = 1.2 atm

[tex]P_2[/tex] = Final pressure = [tex]3.00\times 10^{-3}[/tex] atm

[tex]V_1[/tex] = Initial volume = 1.00 L

[tex]V_2[/tex] = Final volume = ?

[tex]T_1[/tex] = Initial temperature = [tex]25^oC=[25+273]=298K[/tex]

[tex]T_2[/tex] = Final temperature = [tex]-23^oC=[-23+273]=250K[/tex]

Putting values in above equation, we get:

[tex]\frac{1.2atm\times 1.00L}{298K}=\frac{3.00\times 10^{-3}atm\times V_2}{250K}\\\\V_2=\frac{1.2\times 1.00\times 250}{298\times 3.00\times 10^{-3}}\\\\V_2=335.6L[/tex]

Hence, the final volume of the balloon is 335.6 L

Answer:

its D.

Explanation:

Answer:

149.09 g/mol GOOD LESSONS ♡

Answer:

The answer is 149.09 g/mol

Explanation:

I hope this helps!!

Answer:

Mass is amount of matter. Weight is how that matter is affected by gravity.

Explanation:

Answer:

A2+

..........

Explanation:

they lose 2 electrons to form an ion

Answer:A chlorine atom in its ground state has a total of seven electrons in orbitals related to the atoms third energy level.

Explanation:

The volume of Oxygen at STP required : 251.25 L

Conditions at T 0 ° C and P 1 atm are stated by STP (Standard Temperature and Pressure). At STP, Vm is 22.4 liters/mol.

Reaction(combustion) :

2C₂H₂(g)+5O₂(g)⇒4CO₂(g)+2H₂O(g)

mol C₂H₂ :

[tex]\tt \dfrac{100.5}{22.4}=4.49[/tex]

mol ratio C₂H₂ : O₂ = 2 : 5, so mol O₂ :

[tex]\tt \dfrac{5}{2}\times 4.49=11.23[/tex]

volume  O₂ at STP :

[tex]\tt 11.23\times 22.4=251.55~L[/tex]

Or you can use Avogadro's hypothesis :

In the same temperature and pressure, in the same volume conditions, the gas contains the same number of molecules  

So the ratio of gas volume will be equal to the ratio of gas moles  :

[tex]\tt \dfrac{V_1}{V_2}=\dfrac{n_1}{n_2}\\\\\dfrac{100.5}{V_2}=\dfrac{2}{5}\\\\V_2=\dfrac{100.5\times 5}{2}=251.25~L[/tex]

Answer: Bismuth (Bi) , Nitrogen family

Explanation:

As the element has 5 valence electrons in the sixth energy level, which mens it belongs to 6th period as the valence electron has entered the 6th energy level.

Now as the electrons are  filled according to afbau's rule , the electronic configuration of the element will be :

[tex][Xe]4f^{14}5d^{10}6s^26p^3[/tex]

Now as the atomic number of element is equal to the number of electrons in a neutral atom , the atomic number is 83 and the element is Bismuth (Bi). As the last electron enters p -subshell , it is  a p block element. It lies in group 15 which is nitrogen family.

Answer:

B. 313.8

Explanation:

Answer:

Explanation:

While trying to write the chemical formula for a compound (a neutral molecule), one must identify and exchange the charge of the cation with that of the anion to become the subscript of one other. For example

Aluminium oxide has Aluminium (Al) and oxygen (O); since Al has a charge of 3+ (the cation) and O has a charge of 2- (the anion), the compound would have it's charges as Al³⁺O²⁻ and when the charges are exchanged to there subscripts, it would form Al₂O₃; thus there would be two cations of aluminium for every three anions of oxygen in order to have a neutral molecule.

This same explanation can be given to Aluminium sulfite. Aluminium sulfite has Aluminium (Al) and sulfite (SO₃). Al has a charge of 3+ (cation) while sulfite has a charge of 2- (anion), with the compound having it's charges as Al³⁺(SO₃)²⁻ and when the charges are exchanged to there subscripts, it would form Al₂(SO₃)₃ and would thus have 2 cations of aluminium (Al³⁺) for every 3 anions of sulfite (SO₃³⁻) in order to have a neutral molecule.

Answer:

Josh is running at a speed of 9.09 yards per second.

Josh's velocity is 9.09 East.

Josh's force is 900 N.

Aaron Donald's force is 845 N.

Yes Josh scores the touchdown because he is faster and has more mass than Donald.

Explanation:

Josh scores the touchdown as he is heavier and faster than Donald.

Formulas are:

Force= mass x acceleration

Speed= distance divided by time.

Velocity= distance divided by time.

Molarity is the amount of solute in 1L of solution while percent by mass is the ratio of the mass solute to the mass of solution multiplied by 100. Both quantities are used measure the amount of solute in solution.

The question is incomplete however, I will try to explain molarity and percent by mass.

The term molarity means the number of moles of a substance is 1 L of solution while the percent by mass is the ratio of the mass solute to the mass of solution multiplied by 100.

Both molarity and percent by mass shows the amount of solute in a solution.

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Answer:

Both are ratios of the amount of solute over the amount of solution/

Explanation:

took test.

Answer:

Velocity

Explanation:

Answer: velocity I’m sure

Explanation:

Answer:

In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed. The distinction between physical and chemical change is not clear cut.

Explanation:

Answer:

21.3dm³

Explanation:

Given parameters:

Initial volume of gas = 3dm³

Initial pressure  = 101kPa

Final pressure  = 14.2kPa

Unknown

Final volume  = ?

Solution:

To solve this problem, we use the Boyle's law which states that "the volume of a fixed mass of a gas varies inversely as the pressure changes if the temperature is constant".

Mathematically;

                P₁ V₁  = P₂ V₂

P and V are pressure and Volume

1 and 2 are the initial and final states

Now insert the parameters and solve;

         101 x 3 = 14.2 x V₂  

                  V₂  = 21.3dm³

Answer:

Mesosphere

Stratosphere

Thermosphere

Troposphere

Exosphere

Explanation:

The exosphere refers to the farthest region of the atmosphere that gradually fades into space.

The troposphere is the lowest layer of atmosphere. It is the layer where weather changes occur.

The thermosphere is right above the mesosphere but just below the exosphere. It is the layer where photoionization/photodissociation of molecules occurs thereby creating ions. This largely owes to interaction of molecules in this layer with ultraviolet radiation.

The stratosphere is composed of gases. Prominent among them is ozone which serves as a blanket against the sun's ionizing radiation.

The mesosphere lies above the stratosphere but just below the thermosphere. Temperature decreases steadily with height in the mesosphere.

Answer:magnesium plus nitrogen is : magnesium nitride

Explanation:

The new pressure will be : 25 atm

Boyle's Law  

At a constant temperature, the gas volume is inversely proportional to the pressure applied  

[tex]\rm p_1V_1=p_2.V_2\\\\\dfrac{p_1}{p_2}=\dfrac{V_2}{V_1}[/tex]

P₁=15 atm

V₁=5 L

V₂= 3 L

[tex]\tt P_2=\dfrac{P_1.V_1}{V_2}\\\\P_1=\dfrac{15~atm\times 5~L}{3~L}\\\\P_1=\boxed{\bold{25~atm}}[/tex]