Question

Can someone please help me with my homework ASAP? It's due tonight.

Answer 1

Answer:

27.7 grams of Li

0.140 moles of Co

0.158 moles of K

59.9 grams of As

8.00x10⁻⁹ moles of U

142.8 moles of H

0.0199 moles of O

0.666 moles of Pb

Explanation:

Mass / Molar mass = Mol

Mol . Molar mass = Mass

3.99 m . 6.94 g/m = 27.7 grams of Li

8.28 g / 58.93 g/m = 0.140 moles of Co

6.17 g / 39.1 g/m = 0.158 moles of K

0.8 mol . 74.92 g/m = 59.9 grams of As

6.02x10²³ (NA) particles are contained in 1 mol

6.02x10²³ are contained in 1 mol U____ 1 mol  H ____ 1 mol O ___ 1 mol Pb

4.82x10¹⁵ atoms U  ____ 4.82x10¹⁵/ 6.02x10²³ = 8.00x10⁻⁹ moles of U

8.60x10²⁵atoms H  ____ 8.60x10²⁵ / 6.02x10²³  = 142.8 moles of H

1.20x10²² atoms O  ____ 1.20x10²² / 6.02x10²³ = 0.0199 moles of O

4.01x10²³ atoms Pb ____ 4.01x10²³ / 6.02x10²³ = 0.666 moles of Pb

Answer 2

Answer:

1) 27.69 grams Li

2) 0.138 moles Co

3) 0.0736 moles Kr

4) 59.94 grams As

5) 8*10^-9 moles U  = 1.9*10^-6 grams U

6) 142.81 moles H = 144.24 grams H

7) 0.0199 moles O = 0.3184 grams

8) 0.666 moles Pb = 138 grams

Explanation:

Step 1: Data given

Moles = mass / molar mass

mass = moles * molar mass

3.99 mol Li to g Li

⇒ Molar mass of Li = 6.94 g/mol

mass of Li = 3.99 grams * 6.94 g/mol = 27.69 grams

8.28 g Co to mol Co

⇒ Molar mass of Co = 58.93 g/mol

Moles of Co = 8.28 grams / 59.93 g/mol = 0.138 moles

⇒ Molar mass of Kr = 83.80 g/mol

Moles of Kr = 6.17 grams / 83.80 g/mol = 0.0736 moles

0.8000 mol As to g As

⇒ Molar mass of As = 74.92 g/mol

Mass of As = 0.8000 mol * 74.92 g/mol =  59.94 grams

4.82*10^15 atoms U

⇒ 1 mol = 6.022*10^23 atoms

4.82*10^15  = 1/6.022*10^23 * 4.82*10^15 = 8*10^-9 moles U

8*10^-9 moles U *238.03 = 1.9*10^-6 grams

8.60*10^25 atoms H

⇒ 1 mol = 6.022*10^23 atoms

8.60*10^25  = 1/6.022*10^23 * 8.60*10^25 = 142.81 moles U

142.81 moles H *1.01 = 144.24 grams

1.20*10^22 atoms O

⇒ 1 mol = 6.022*10^23 atoms

1.20*0^22  = 1/6.022*10^23 * 1.20*10^22 =0.0199 moles U

0.0199 moles O * 16g/mol = 0.3184 grams

4.01*10^23 atoms Pb

⇒ 1 mol = 6.022*10^23 atoms

4.01*10^23  = 1/6.022*10^23 * 4.01*10^23 =0.666 moles U

0.666 moles Pb * 207.2 g/mol = 138 grams