1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Zina [86]
3 years ago
10

What amount (moles) is represented by each of these samples?

Chemistry
1 answer:
Zinaida [17]3 years ago
5 0
<h3>Answer:</h3>

                  a)  Moles of Caffeine  =  1.0 × 10⁻⁴ mol

                  b) Moles of Ethanol   =  4.5 × 10⁻³ mol

<h3>Solution:</h3>

Data Given:

                  Mass of Caffeine  =  20 mg  =  0.02 g

                  M.Mass of Caffeine  =  194.19 g.mol⁻¹

                  Molecules of Ethanol  =  2.72 × 10²¹

Calculate Moles of Caffeine as,

                               Moles  =  Mass ÷ M.Mass

Putting values,

                               Moles  =  0.02 g ÷ 194.19 g.mol⁻¹

                                Moles  =  1.0 × 10⁻⁴ mol

Calculate Moles of Ethanol as,

                                                         As we know one mole of any substance contains 6.022 × 10²³ particles (atoms, ions, molecules or formula units). This number is also called as Avogadro's Number.

The relation between Moles, Number of Particles and Avogadro's Number is given as,

                          Number of Moles  =  Number of Molecules ÷ 6.022 × 10²³

Putting values,

                          Number of Moles  =  2.72 × 10²¹ Molecules ÷ 6.022 × 10²³

                          Number of Moles  =  4.5 × 10⁻³ Moles

You might be interested in
A 0.45-g sample of aspirin is decomposed into its constituent elements and found to contain 0.27 g C, 0.020 g H, and 0.16 g O. C
slamgirl [31]

Answer:

Explanation:

mass % of C = 0.27/0.45*100 = 60%

mass % of H = 0.02/0.45*100 = 4.4%

mass % of O = 0.16/0.45*100 = 35.6%

Total = 60%+4.4%+ 35.6% = 100%

3 0
3 years ago
Cellular respiration uses glucose and oxygen, which have high levels of free energy, and releases carbon dioxide and water, whic
Alja [10]

Answer: Cellular respiration is spontaneous and exergonic. The energy released from the glucose is stored in ATP molelcules.

Explanation:

Spontaneous reactions have an increase in entropy (level of disorder) and a decrease in enthalpy (total energy). Cellular respiration goes from a more ordered state (one molecule of glucose) to a more disordered state (several molecules of CO2), and goes from a state with a lot of free energy to one with much less free energy. As a result, respiration is a spontaneous process.

As free energy from the glucose is released as ATP molecules during oxidation, the reaction is exergonic.

4 0
3 years ago
Read 2 more answers
Which part of atom is responsible for chemical bonding
yulyashka [42]

Answer:

electrons are responsible for the chemical bonding

6 0
3 years ago
How do the properties of the elements change as you move across a period on a periodic table from left to right?
Tomtit [17]
B) The elements become less reactive.
8 0
3 years ago
The Earth's asthenosphere is a structural layer made up on what?
ehidna [41]
Gas is the answer ok
5 0
3 years ago
Read 2 more answers
Other questions:
  • What would the formula of gallium<br> bromide be?
    14·1 answer
  • What is the name for SO2
    5·1 answer
  • In the simulation, open the Micro mode, then select the solutions indicated below from the dropdown list above the beaker. The b
    9·1 answer
  • Is sand biotic or abiotic
    7·1 answer
  • When a chemical reaction occurs, what happens to the atoms of the two substances?
    14·2 answers
  • "All is strange and vague."
    5·2 answers
  • How does temperature differ from heat?
    13·1 answer
  • Which is the correct Lewis dot structure of NH2?<br><br> A. A<br> B. B<br> C. C<br> D. D<br> E. E
    10·2 answers
  • HIGH POINTS BRAINLIEST!! HURRY
    6·1 answer
  • The burning of magnesium is a highly exothermic reaction. How many kilojoules of heat are released when 0. 75 mol of Mg burn in
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!