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2 years ago

When a bullet is fired from a gun what is true about the momentum

1 answer:

8 0

Before the bullet is fired the momentum is Zero because nothing is moving but once the bullet is shot the momentum increases because of the movement of the bullet moving forward.

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A 251 ml sample of 0.45M HCl is added to 455 mL of distilled water. What is the molarity of the

Oksi-84 [34.3K]

We are given:

251 mL sample of 0.45M HCl added to 455 mL distilled water

Whack a mole! (finding the number of moles):

We know that in order to find molarity, we use the formula:

Molarity = number of moles / Volume (in L)

so, number of moles is:

Number of moles = Molarity * Volume(in L)

now let's plug the values for the HCl solution to find the number of moles

Number of moles = 0.45M * 0.251 L

Number of moles = 0.113 moles

Time to concentrate (finding the final concentration):

Total final volume = 251 mL + 455 mL = 706 mL = 0.706 L

Number of moles of HCl = 0.113 moles

Molarity = Number of moles / Volume (in L)

Molarity = 0.113 / 0.706

Molarity = 0.16 M

___________________________________________________________

BONUS METHOD TIME!!!

We know the relation:

M1 * V1 = M2 * V2

where M1 and M2 are the initial and final molarities and V1 and V2 are initial and final volumes respectively

notice that I didn't mention that the volume has to be in Liters, that's because of the units being concerned with both sides of the equation, say I have the volume in mL and want to convert both these volumes to L, I would divide both sides by 1000, which would NOT change the overall value

Now, plugging values in this equation

(0.45) * (251) = (251 + 455)* (M2)

112.95 = (706)(M2)

M2 = 112.97/706 [dividing both sides by 706]

M2 = 0.16 Molar

8 0

2 years ago

Calculate the number of C atoms in 0.190 mole C6H14O. can anyone help me on this one?

likoan [24]

In 0.190 mole of C6H14O, there is 0.190*6 (number of C in one molecule) = 1.140 mole of C atoms. The total number of C atoms = 1.14 * 6* $10^{23}$ (atoms of C in one mole) = 6.84* $10^{23}$ atoms.

8 0

2 years ago

For a particular redox reaction, Cr is oxidized to CrO 2 − 4 and Ag + is reduced to Ag . Complete and balance the equation for t

Sunny_sXe [5.5K]

Answer:

6Ag⁺ + Cr + 8OH⁻ → 6Ag + CrO₄²⁻ + 4H₂O

Explanation:

We can balance the redox reaction of Cr and Ag⁺, in terms of two half-reactions, one for Ag⁺ and other for Cr:

Ag⁺ → Ag

In the above equation we need to balance the number of electrons, we know that the Ag⁺ is being reduced to Ag, so the reaction is:

Ag⁺ + e⁻ → Ag (1)

Now, we need to balance the half-reaction of Cr:

Cr → CrO₄²⁻

From above, we know that the Cr is being oxidated to CrO₄²⁻, so we need to balance the number of electrons and the number of oxygen atoms. The Cr⁰ is being oxidated to Cr⁶⁺, so for the electron balance, we need to add 6e⁻ to the right side of the equation. Since the reaction is in a basic medium, the oxygen atoms will be balanced with OH⁻ ions as follows:

Cr + OH⁻ → CrO₄²⁻ + 6e⁻

The hydrogen atoms will be balanced using H₂O molecules:

Cr + OH⁻ → CrO₄²⁻ + 6e⁻ + H₂O

The balanced equation is:

Cr + 8OH⁻ → CrO₄²⁻ + 6e⁻ + 4H₂O (2)

Since the reaction (1) involves 1 electron and the reaction (2) involves 6 electrons, by increasing the reaction (1) six times and by the addition of the two reactions (1 and 2) we can have the net redox reaction:

6*(Ag⁺ + e⁻ → Ag)

Cr + 8OH⁻ → CrO₄²⁻ + 6e⁻ + 4H₂O

6Ag⁺ + Cr + 8OH⁻ → 6Ag + CrO₄²⁻ + 4H₂O

Therefore, the net equation is: 6Ag⁺ + Cr + 8OH⁻ → 6Ag + CrO₄²⁻ + 4H₂O.

I hope it helps you!

7 0

2 years ago

Calculate the energy provided by a slice of bread containing 2 g of protein, 1 g of fat, and 20 g of carbohydrate. record your a

vichka [17]

the energy gained by proteins and carbohydrates differs from the energy gained by fats.
proteins and carbohydrates both give 4 kcal per gram
fats give 9 kcal per gram
mass of proteins - 2 g
energy given by proteins - 2 g x 4 kcal/g = 8 cal
mass of carbohydrates - 20 g
energy given by carbohydrates - 20 g x 4 kcal/g = 80 cal
mass of fat - 1 g
energy given by fat - 1 g x 9 kcal/g = 9 cal
total energy = 8 + 80 + 9 = 97 kcal
energy = 97 kcal

8 0

2 years ago

The concentration of reactants and products and the rate of reaction were measured during a chemical reaction. After the first 3

igomit [66]

Answer: B

Explanation:

4 0

1 year ago