Chemistry Homework Help

Chemistry
Tutor: None Selected Time limit: 1 Day

Jun 5th, 2015

Thank you for the opportunity to help you with your question!

DATA:

Number of atoms= 7.5*1015

Mass in grmas=?

SOLUTION:

6.02*1023 atoms are present in 1 mol of Ni

7.5*1015 atoms are present in (1*7.5*1015)/6.02*1023

  = 1.2458*10-8 mol

Mole of Ni = mass of Ni in grmas/ atomic mass of Ni

Mass of Ni= mole of Ni * atomic mass of Ni

Mass of Ni = 1.2458*10-8 * 58.6934

Mass of Ni = 7.3123*10-7g

DATA:

Mass of aspirin= 0.1g

Number of molecules = ?

SOLUTION:

Mole of aspirin = mass of aspirin/ molecular mass of aspirin

  = 0.1 /180

  = 5.5555*10-4

1 mol aspirin contains 6.02*1023 molecules

5.5555*10-4 contains (6.02*1023* 5.5555*10-4)

  =3.3444*1020 molecules


Please let me know if you need any clarification. I'm always happy to answer your questions.
Jun 5th, 2015

i am getting back to you with the solution of other three in a while. hope you'll understand

Jun 5th, 2015

DATA:

Percentage of Ag= 63.5%

Percentage of N=  8.25%

Percentage of O2 = 100-63.5-8.25= 28.25%

Empirical formula=?

SOLUTION

STEP 1:

DETERMINE MOLES

Mol of Ag = 63.5/107.86 = 0.5887mol

Mole of N = 8.25/14.00 = 0.5892mol

Mole of O2 = 28.25/15.99 = 1.7667mol

STEP 2:

DTERMINE RATIOS

Ag= 0.5887/0.5887 = 1

N= 0.5892/0.5887 = 1.000

O2 = 1.7667/0.5887 = 3.00

STEP 3:

WRITW EMPIRICAL FORMULA

AgNO3

DATA:

Molecular mass = 42g/mol

Empirical formula = CH2

Molecular formula =?

SOLUTION:

STEP 1:

DETERMINE ā€˜nā€™

n = molecular mass/empirical formula mass

n= 42/14

n= 3

STEP 2

DTERMINE MOLECULAR FORMULA

Molecular formula = (empirical formula)n

Molecular formula = (CH2)3

Molecular formula = C3H6

DATA:

Mass of sample= 60g

Percentage of Pb = 64%

Percentage of C = 29.7%

Percentage of H = 6.2%

Empirical formula=?

SOLUTION:

STEP 1

DETERMINE MASS OF ELEMENTS IN THE GIVEN MASS OF SAMPLE

Mass of Pb= (64*60)/100 = 38.4g

Mass of C= (29.7*60)/100 = 17.82g

Mass of H = (6.2*60)/100 = 3.72g

STEP 2

DETERMINE MOLES

Moles of Pb = 38.4/207.2 = 0.1853mol

Moles of C = 17.82/12.01= 1.4837mol

Moles of H= 3.72/1.00 = 3.72mol

STEP 3

DETERMINE RATIOS

Pb= 0.1853/0.1853 = 1

C= 1.4837/0.1853= 8.00

H= 3.72/0.1853= 20.07

STEP 4

WRITE EMPIRICAL FORMULA
C8H20Pb


Jun 5th, 2015

Studypool's Notebank makes it easy to buy and sell old notes, study guides, reviews, etc.
Click to visit
The Notebank
...
Jun 5th, 2015
...
Jun 5th, 2015
Mar 29th, 2017
check_circle
Mark as Final Answer
check_circle
Unmark as Final Answer
check_circle
Final Answer

Secure Information

Content will be erased after question is completed.

check_circle
Final Answer