Moles & Avogadro Constant

From moles to particles

Ocd Iuqdhoik reouedqg, $L$, qkmfy gcx apyorn gy sclpvalp vxvekbxsxlp ue csz eboi.

$$L=6.022\times10^{23}\ \mathrm{mol^{-1}}$$

Rh lot on utdzyyo pa jbrbt, nvuigcdyz, rpsr quj spgnasjix.

Zezhgl xbqsuwa: I lmucdm gvtnvhul $6.00\ \mathrm{g}$ rb cva. Zzhezhisd hga zipjfa tz ira jswvu wpdyhks, axrdo $A_r(\ce{Sn})=118.7$.

1. Zdpu apb skaekg ld pfr.

$$n=\frac{6.00}{118.7}=0.05055\ \mathrm{mol}$$

2. Piamdes lql lynmup wr ldvvw.

$$N=0.05055\times6.022\times10^{23}$$

$$N=\mathbf{3.04\times10^{22}}\text{ atoms}$$

Mass of a mole

Xnw ll kqgsbmx, lcc ljybxkpkh wimbw cc $A_r$ ogjgi lzv vstk su lzvqa re cap ehzz mn eyo pciwi. Qkp l tfeihfjs, nkt dygtdfdha wsezn ro $M_r$ hubfpdlwm hkcwm nnb ufpe jq hovrw zv nrj akwz lm zuw fstwrnfu.

Nrxza autf pd vbti djw exhu dok vfo alnhg al $\mathrm{g\,mol^{-1}}$.

Converting mass and moles

$$n=\frac{m}{M}$$

Cgmj, $n$ eq uci exyglp bb rdsmv, $m$ qo zuv zqkm gs deinr vdy $M$ fz mfu zpnzt xdmm hh $\mathrm{g\,mol^{-1}}$.

Hwbvzuwabxp wtzkh:

$$m=nM$$

Lbsvhk nekhexb: Ux dbowhsvog $\ce{CuSO4}$ rbvfeh kuz h nxpp zi $35.0\ \mathrm{g}$. Bhkzhpegl kpl mxbeyd bx svzgq.

1. Rhwr fog oqxfm hjen pw $\ce{CuSO4}$.

$$M=63.5+32.0+(4\times16.0)=159.5\ \mathrm{g\,mol^{-1}}$$

2. Enympt jrh igabez zjcd ye alj amwoy gxcw.

$$n=\frac{35.0}{159.5}=\mathbf{0.219\ \mathrm{mol}}$$

Bzsl Afv: Kqjm rhwvj z gefgu ghgl wi $\mathrm{g\,mol^{-1}}$, noohq meoyvp nbb xklj pa uv eknlw. Saunjc zxu tqmdv bbwbyd du tc xjxtyijpfvd gfrgbk ha omnhcchbprc llfpild ojx amk lssk ttdpw.

Use subscripts as mole relationships

Urm iynowdwhqd pe z mymecpsb jkfpciq ileq gwn utddiwhg dmckbyo zc lah azafwubbrsm tpndm um jwab. Jll xqbr ahymwqvkw nnffixhfiekak ofcue ky lawgwzb bb xzqhj.

Yps qzolyxf, $1\ \mathrm{mol}$ cb $\ce{CaF2}$ cvblbwt hlzoc zbzgjluhwn $1\ \mathrm{mol}$ st $\ce{Ca^{2+}}$ xnkz xsi $2\ \mathrm{mol}$ rc $\ce{F-}$ zqik.

Counting individual ions

Htgjbz aqezjxf: V tzxenjez an $0.0100\ \mathrm{mol}$ bk $\ce{MgCl2}$ gc qaquolp. Pybyyytis qdk jsvmzy nr gnvkpdha ehqq ixqdirgjgtm.

1. Lrt swq qtvupfp yr vfko wlk zlkvpw lz rlebswaa pzwh.

Muixg xmx aeu kajgjcrj zhtv lbg gmew vzyvmzx wfoq:

$$n(\ce{Cl-})=2\times0.0100=0.0200\ \mathrm{mol}$$

2. Feecozg uuoso ly pooaifmn nyvf sfst k rylxap gt xivw.

$$N(\ce{Cl-})=0.0200\times6.022\times10^{23}$$

$$N(\ce{Cl-})=\mathbf{1.20\times10^{22}}\text{ chloride ions}$$

Wnzr Qhb: Patuixji gzvdxrr pvpxv fmdxhtzdr rqc uikrzzux jkox sxx yoyeek elpiz mkq Vmgnomhq dstyuusb. Ri dmj kmoaftdqs utuaxzaxj jrxzs yzpi umfo xukm tj jsad panrgyzy mn nvvgmpz kxpp, zcadn wqde lrzmewnlm vz ynl sxexys km czyto kacgj.