Chemistry Problem (1 Viewer)

[Real Madrid]

Solve showing calculations

Work out the amount of formula units in 7.5 moles of potassium bromide (KBr)

 

[selablad]

n = no of rep. particles/ N_A

(n = number of moles, N_A = Avagadro's number, rep. particles in this case being formula units)

7.5 = x/N_A

x = 7.5 x 6.02x10^-23
= some number

I think? I hope? Chemistry exam on Wednesday, on the same topic...

 

[Real Madrid]

Mines tommorow.

 

[minijumbuk]

n = no of rep. particles/ N_A

(n = number of moles, N_A = Avagadro's number, rep. particles in this case being formula units)

7.5 = x/N_A

x = 7.5 x 6.02x10^-23
= some number

I think? I hope? Chemistry exam on Wednesday, on the same topic...

I think that is incorrect. I believe the formula units is the total number of atoms, so it should be 15 x 6.022x10²³

Also, Avogadro's constant is not to the power of -23, but positive 23.

 

[selablad]

Oops about Avagadro's constant. Thanks

I'm pretty sure the formula units thing is right though. They'd have asked for number of atoms if they wanted that, surely?

A formula unit in chemistry is the empirical formula of an ionic or covalent network solid compound used as an independent entity for stoichiometric calculations. It is the lowest whole number ratio of ions represented in an ionic compound. Examples include ionic NaCl and K2O and covalent networks such as SiO2 and C (as diamond or graphite).

Ionic compounds do not exist as individual molecules; a formula unit thus indicates the lowest reduced ratio of ions in the compound.

A formula unit shows the kinds and numbers of atoms in the smallest representative unit of a substance.

 

[selablad]

Pretty much, yeah.

 

[minijumbuk]

Haha, if wiki says it's right, I guess it's right xD

Haven't touched formula units for a whole year xD

 

[selablad]

Haha, if wiki says it's right, I guess it's right xD

All hail wikipedia.