Please help. Which of these are chemical or physical change?

Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\[/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

We have

[tex]n = \frac{1.00 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{1}{6.02} \\ = 0.166112[/tex]

We have the final answer as

Hope this helps you

Answer: Exothermic because the ΔH is negative.

Explanation:

The standard enthalpy of formation or standard heat of formation of a compound is the change of enthalpy during the formation of 1 mole of the substance from its constituent elements, with all substances in their standard states.

[tex]C(s)+O_2(g)\rightarrow CO_2(g)[/tex]

Exothermic reactions are those reactions in which heat is released and [tex]\Delta H[/tex] is negative.Endothermic reactions are those reactions in which heat is absorbed and [tex]\Delta H[/tex] is positive.

The reaction is exothermic as the heat is released during the formation of [tex]CO_2[/tex] as heat of formation of [tex]CO_2[/tex] is negative.

Answer: Maybe, It could be a good and bad idea.

Explanation:

This is beacuse Metal does not absorb and can block sunlight.

Answer:

body temperature and energy

Explanation:

a. pressure always favors the side with fewer molecules. in this reaction as both the sides have equal number of molecules, there won't be any change in the position of the equilibrium.

b. when the concentration of the hydrogen gas is increased. more particles would take place in the reaction and so, the rate of reaction would increase favoring the reaction concerning hydrogen gas molecules (backward reaction in this case) therefore, equilibrium would shift to the backward reaction (left).

c. as forward reaction is endothermic, when temperature is increased the equilibrium will shift to the forward reaction (right).

d. catalyst would not have any effect on the position of the equilibrium. it will only increase the rate of reaction.

hope it helps. :)

Answer:

A

Explanation:

Answer:

“Newton’s Law of Gravity” gives the gravity force between two objects with masses m

and M separated by distance r:



F  G

m M

r

2

G is called the Gravitational Constant, and has the value



6.671011N m

2

kg2

(N is for

Newton, the physicists’ unit of force) or



1.51011 lbm

2

kg2

.

Let’s go back to the example given in the text: two 150 lb people separated by 1 meter.

The mass of each person is



150lb

2.2

lb

kg

 68kg

. Putting these into the formula gives



F 1.5101 1 lb m

2

kg2



(68kg)

2

(1m)

2

107

lb.

Newton’s Law of Gravity actually gives the force only between two small objects. If one

of the objects is a sphere (such as the Earth) then it turns out that you can still use the

formula, but you must use the distance to the center of the sphere as the value for r. As

an example, let’s put in numbers for a 1 kg object sitting on the surface of the Earth.

Then the force of attraction is given by the gravity equation with m = 1 kg, M = the mass

of the Earth =

24 610

kg, and r = radius of the Earth (that’s the distance to the center of

the sphere). This distance is r = 6371 km ≈

6

610

meters. Without plugging in the

numbers, can you guess what the answer will turn out to be? Guess, and then check this

footnote2

to see if you guessed correctly.

Suppose you weigh 150 lbs on the Earth. Then your mass is



150lb

2.2

lb

kg

 68kg

. What will

you weigh on the Moon? We can calculate that by using Newton’s Law of Gravity, and

putting in the M = the mass of the Moon =

22 7.310

kg, r = the radius of the moon =

6

1.710

meters. The answer is F = 25 lb. That means you will weigh 25 lb. on the

surface of the Moon.

Explanation:

hope this helps :)

Answer:

pressure of gas are constant describe the relationship between moles and temprature

The statements correctly describes the relationship between volume and temperature is pressure of gas are constant.

The force delivered perpendicularly to an object's surface per unit area across which that force is dispersed is known as pressure. In comparison to the surrounding pressure, gauge pressure is the pressure. Pressure is expressed using a variety of units.

The volume of a gas is directly proportional to the number of moles of gas when both temperature and pressure are constant. The pressure of a gas is directly proportional to the number of moles of gas when both temperature and volume are constant.

In layman's words, the volume of a fixed mass of gas is exactly proportional to temperature at constant pressure.

Thus, If the pressure and temperature remain constant, the volume of a gas is directly proportional to the number of moles in the gas.

To learn more about the pressure, follow the link;

https://brainly.com/question/28169433

#SPJ12

Answer:

V₂ = 13.44 L

Explanation:

Given that,

Initial volume, V₁ = 5 L

Initial pressure, P₁ = 0.863 atm

Final pressure, P₂ = 0.321 atm

We need to find the final volume of the balloon. The relation between the volume and pressure is given by :

[tex]P_1V_1=P_2V_2[/tex]

Where

V₂ is the volume of the balloon

So,

[tex]V_2=\dfrac{P_1V_1}{P_2}\\\\V_2=\dfrac{0.863 \times 5}{0.321 }\\\\V_2=13.44\ L[/tex]

So, the final volume of the balloon is equal to 13.44 L.

H⁣⁣⁣⁣ere's l⁣⁣⁣ink t⁣⁣⁣o t⁣⁣⁣he a⁣⁣⁣nswer:

bit.[tex]^{}[/tex]ly/3a8Nt8n

Answer:

218.98 grams

Explanation:

Given that,

No. of moles, n = 2.3

The molar mass of magnesium chloride is 95.211 g/mol.

We need to find the mass of 2.3 moles of magnesium chloride.

We know that,

No. of moles = given mass/molar mass

Let m be the given mass. So,

[tex]m=n\times M\\\\=2.3\times 95.211 \\\\=218.98\ g[/tex]

So, the required mass is equal to 218.98 grams.

Answer:

Zn is the excess reagent

Explanation:

Answer:

Mountain ranges and prevailing winds.

Explanation:

Mountain ranges and prevailing winds are the factors that is responsible for the difference in the precipitation between Nevada and Washington states. The Washington state is located along the coastal region of pacific ocean and having more mountain ranges which causes more rainfall in that region while on the other hand, Nevada state comprise of plateau, basins and far away from the ocean which is the main cause of lower rainfall as compared to Washington state.

Answer:

d. 200.

Explanation:

The reaction is:

2KMnO4 + 16HCl ----> 2KCl + 2MnCl2 + 8H2O + 5Cl2

So 2 moles of KCL are produced form  16 moles of HCL

So 25 moles KCL are made from   25 * (16/2) HCl.

= 25 * 8

= 200 moles. HCl.

Answer:

(B) Grasses to Grasshoppers to Birds to Foxes

Explanation

Answer:c

Explanation:

Answer:

what is your question?

Explanation:

I don't understand

Answer:

ujdbdbfbf fbFbsygtsjysnsgndhngsnsgnafbfa

Answer:

823.98

Explanation:

Since there is only one Ba per atom you simply times 1 by 6 to get the number of mols of Ba per atom, then you times this by the atomic mass of Ba on the periodic table

A neutral solution is one that is neither acidic nor basic. The hydrogen ion concentration equals the hydroxide ion concentration, and both equal 1 X 10-7 M. In a neutral solution, then, pH = pOH = 7.

they remain as they are and don't change their type

Answer:

2(C4H10)+13(O2)->8(CO2)+[](H20)

Explanation:

sorry i couldn’t get the last one

The chemical reaction by providing the correct whole number coefficients: number coefficients will be 2C4H10 + 13O2 WILL GIVE 8CO2 + 10H2O .this will be the balanced reaction.

Balance elements in the equation other than O and H. Balance the oxygen atoms by adding the appropriate number of water ( H 2O) molecules to the opposite side of the equation.

Balance the hydrogen atoms (including those added in step 2 to balance the oxygen atom) by adding H + ions to the opposite side of the equation.

When writing an equation for a chemical reaction, the two sides of the equation should balance and need the same number of each kind of element on both sides.

Therefore the given chemical equation is balanced in the following form, 2C4H10 + 13O2 WILL GIVE 8CO2 + 10H2O

Learn more about the balanced equation, here :

https://brainly.com/question/14263388

#SPJ2

Answer:

a.) exothermic

b.) 2,800.6 J

Explanation:

The Fe is our limiting reactant here. First, convert the mass of Fe given to moles of Fe by dividing mass by the molar mass:

(51.3 g Fe)/(55.845 g/mol) = 0.9186 mol Fe.

According to the balanced equation, 2 moles of Fe2O3 are produced for every 4 moles of Fe that are consumed. In other words, half as many moles of Fe2O3 will be produced as there are Fe that react:

(0.9186 mol Fe)(2 mol Fe2O3/4 mol Fe) = 0.4593 mol Fe2O3.

Finally, convert the moles of Fe2O3 back to grams by multiplying by the molar mass of Fe2O3:

(0.4593 mol Fe2O3)(159.6882 g/mol) = 73.3 g Fe2O3.

So, 73.3 grams of Fe2O3 are formed.

Answer:

[tex]186.01\ \text{mL}[/tex]

Explanation:

[tex]P_1[/tex] = Initial pressure = 1.47 atm

[tex]P_2[/tex] = Final pressure = [tex]10^5\ \text{Pa}[/tex]

[tex]T_1[/tex] = Initial temperature = [tex]44^{\circ}\text{C}[/tex]

[tex]T_2[/tex] = Final temperature = [tex]273.15\ \text{K}[/tex]

[tex]V_1[/tex] = Initial volume = 145 mL

[tex]V_2[/tex] = Final volume

We have the relation

[tex]\dfrac{P_1V_1}{T_1}=\dfrac{P_2V_2}{T_2}\\\Rightarrow V_2=\dfrac{P_1V_1T_2}{T_1P_2}\\\Rightarrow V_2=\dfrac{1.47\times 101325\times 145\times 273.15}{(44+273.15)\times 10^5}\\\Rightarrow V_2=186.01\ \text{mL}[/tex]

Final volume of the sample is [tex]186.01\ \text{mL}[/tex].

Answer:

 They both are made up of atoms and having bonds linking their atoms together.molecules and compounds also share the qualities of being both pure and homogeneous substances.

Explanation:

Hope this helped!!!