Question #c2d91

2 Answers
Feb 17, 2018

Answer:

Around #1.06*10^24# ions

Explanation:

#OH^-# has a molar mass of #17 \ "g/mol"#.

So, in #30 \ "g"# of hydroxide ions. there exists #(30cancel"g")/(17cancel"g""/mol")~~1.76 \ "mol"#

In one mole of molecules, there are #6.02*10^23# molecules.

So, there will be a total of

#1.76*6.02*10^23~~1.06*10^24# hydroxide ions.

Feb 17, 2018

Answer:

See below

Explanation:

We know that in 1 Mole we have # 6.022 * 10^23# particles.

In this situation, we aren't given the specified amount of moles, so we have to work them out using the formula:

moles #= (mass) / M_r#

Where the #M_r # is the relative formula mass.

Here we have a mass of #30# and an #M_r# of #17#

#therefore# the amount of moles we have is #30/17# moles.

To work out the number of particles, we multiply the number of moles by Avogadro's constant #(6.022 * 10^23)#

#therefore 30/17 * 6.022 * 10^23 = 1.062705882 * 10^23# ions