How many grams of sodium ions are in na2so4?

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

By what mechanism does cyclohexanol react when treated in sulfuric acid and what compound results?A) E 1; methoxycyclohexane B)

tensa zangetsu [6.8K]

Answer:

E 1: cyclohexene

Explanation:

This reaction is an example of the dehydration of cyclic alcohols. The reaction proceeds in the following steps;

1) The first step of the process is the protonation of the cyclohexanol by the acid. This now yields H2O^+ attached to the cyclohexane ring.

2) the water molecule, which a good leaving group now leaves yielding a carbocation. This now leaves a cyclohexane carbocation which is highly reactive.

3) A water molecule now abstracts a proton from the carbon adjacent to the carbocation leading to the formation of cyclohexene and the regeneration of the acid catalyst. This is an E1 mechanism because it proceeds via a carbocation intermediate and not a concerted transition state, hence the answer.

8 0

3 years ago

If kinetic energy increases does pressure decrease?

enyata [817]

If molecules are in a closed container then we expect the pressure to increase as the kinetic energy increases. This is because the atoms of an element collide with the walls of the container and increase the pressure.

If we use the formula $PV=nRT$ , where P is the pressure, V is the volume, n is the number of moles, R the ideal gas constant and T is the temperature. According to the formula, P is directly proportional to temperature. An increase in temperature leads to an increase in pressure.

Since we know that temperature is the average kinetic energy of molecules present. It means as we increase the temperature we increase the kinetic energy of the molecules which in turn leads to an increase in the pressure.

8 0

3 years ago

Which compound contains both ionic and covalent

musickatia [10]

Answer:

(3) NaNO₃

Step-by-step explanation:

Sodium nitrate has ionic bonds, because it consists of Na⁺ and NO₃⁻ ions.

However, the nitrate ions have covalent bonds between the O atoms and the central N atoms.

(1) and (2) are wrong. Both N₂O₅ and HCl consist of nonmetals, so they are covalent compounds.

(4) is wrong. NaCl has only ionic bonds between the Na⁺ and Cl⁻ ions

7 0

3 years ago

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Hydrofluoric acid is used to etch grooves in glass because it reacts with the silica (sio2(s)) in glass. the products of the rea

kvv77 [185]

Answer is: coefficient is one.
Chemical reaction: SiO₂ + 4HF → SiF₄ + 2H₂O.
Reaction is balanced when there are equal numbers of elements in both side of the chemical reaction.
HF - hydrofluoric acid, highly corrosive, dissolves many materials.
SiF₄ - silicon tetrafluoride.

6 0

3 years ago

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