PRACTICE PROBLEMS Chapter 8 Adapted from Chapter 5 of Introductory Chemistry, 7t

Question

PRACTICE PROBLEMS Chapter 8 Adapted from Chapter 5 of Introductory Chemistry, 7th ed, by Charles J. Corwin NAME(S): SECTION: a) Molar mass of caffeine, CsHrON4O2 b) 6.51 moles of citronellal, a natural insect repellent, CiHisOg c) 124 g ofdiazepam (ingredient ofVALIUM®), Ci6H1OIN2o moles molecules d) 39.7 g of erythrosine, a food coloring, CzoHol4Na Os- Calculate the mass percent composition of each element in the explosive TNT C&H2;(NO2)sCHs. Use three significant figures in your answers. e)

Explanation / Answer

a) molar mass = 12×8+10×1+4×14+2×16=>194g/mol

b) molar mass of citronellal= 154g/mol

mass = mole×molar mass

6.51×154 => 1002.54g

c)mass of diazepam=124g

molar mass of diazepam = 285g/mol

Mole = mass/molar mass

= 124/285 => 0.435mol

d)mass of erothrosine = 39.7g

Molar mass of erothrosine = 880g/mol

Mole = 39.7/880 => 0.045 mol

Number of molecules = 0.045 × NA

Where NA = Avogadro's number = 6.023×1023

e) mass % of C = 12×7×100/227

= 37%

mass % of N = 14×3×100/227 => 18.5%

mass % of H = 1×5×100/227 => 2.2%

mass % of O = 6×16×100/227 => 42.3%

Related Questions

Navigate

• Browse (All)
• Browse P
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.