MOLES science9
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The document discusses the mole concept and how it allows chemists to quantify matter by counting particles using Avogadro's number rather than mass alone. It explains how the mole is defined as 6.022x10^23 particles and can be used to determine the number of atoms in a sample by calculating the number of moles and multiplying by Avogadro's number. Examples are provided to illustrate how to perform mole calculations and determine the number of particles in a chemical substance.
MOLES science9
- 1. Winner takes it all! GUESSTHE NUMBER OF CANDIES INSIDE THE JARTHETEACHER HOLDS
- 3. use the mole concept to express mass of substances; and determine the percentage composition of a compound given its chemical formula and vice-versa.
- 4. How are pieces of matter quantified? How do market vendors sell the rice grains? by getting the mass or by counting? How about eggs? In laboratory, how do chemists measure out a chemical substance?
- 5. Materials Needed: Paper clips of same size Platform balance (preferably with 0.01 precision) PROCEDURE 1. Measure and record the mass of 25 paper clips (A) 2 Divide the mass obtained by 25 to find the average mass of one paper clip.(B) A. Mass ( 25 pcs) g B. Average mass of paper clip
- 6. PROCEDURE 3. Get a handful of paper clips and measure its mass.(C) 4. Determine the number of paper clips by computing, not counting. (D) Total mass/Average Mass of each paper clip 5. Count and record the number of paper clips (E) C. Mass of handful of paper clips D. Number of paper clips based on computation (C/B) E. Number of paper clips based on actual count
- 7. Is the number of paper clips in step 4 the same as the number of paper clips in step 5?Why do you think so? Give some ways in which you can apply this procedure in daily life situations. >packaging volume of materials > repacking goods to be sold in the “sari-sari” store
- 9. How many atoms present in a gold bar? How many molecules presen t in a glass of water?
- 10. It is impossible to count the number of atoms present in a gold bar or the number of molecules present in a glass of water but by knowing their masses, computations can be done which will eventually give the number of particles with the use of a number called Avogadro’s number. 6.02 x 10 23 particles Number of particles in one mole of a substance
- 11. 1 mole = 602213673600000000000000 or 6.022 x 1023 thousands millions billions trillions quadrillions ? There isAvogadro's number of particles in a mole of any substance. AVOGADRO’S NUMBER (Particles in a Mole) Amedeo Avogadro (1766-1856) never knew his own number; it was named in his honor by a French scientist in 1909. its value was first estimated by Josef Loschmidt, anAustrian chemistry teacher, in 1895.
- 12. Chemists also use a unit that is a specified number of particles, most often atoms or molecules. • The unit is called the mole. • A mole (mol) of a substance is 6.022 × 1023 representative particles of that substance • The number of representative particles in a mole and is called Avogadro’s number, 6.022 × 1023 • number of atoms determined experimentally to be found in 12 grams of carbon-12. Counting with Moles
- 13. One mole of marbles would cover the entire Earth (oceans included) for a depth of three miles. One mole of $100 bills stacked one on top of another would reach from the Sun to Pluto and back 7.5 million times. It would take light 9500 years to travel from the bottom to the top of a stack of 1 mole of $1 bills.
- 14. How many molecules are there in 4 moles of CO2? Example
- 15. Note: RULES FOR SCIENTIFIC NOTATION 1. Put your decimal after the first non zero number. 2.Count the number of decimal places moved in Step 1 . If the decimal point was moved to the left, the count is positive. If the decimal point is moved to the right, the count is negative. 3.Write as a product of the number and 10 raised to the power of the count
- 16. Solve. How many mongo seeds are equal to 3.50 moles of mongo seeds?
- 17. Do different material with the same number have the same masses? Do substances with the same mass have the same number of particles? TOTAL COUNT VS MASS
- 18. One mole of different substances always contains 6.02 x 10 23 particles but each of these substances has a different mass.
- 19. CLARIFICATIONS
- 20. Would 1.50 moles of H2O have the same number of particles as 1.50 moles of any of the substances you weighed? One mole of different kinds of substances has the same number of ____________but different ___________. What is the unit that is used by chemists to count particles of substance?
- 21. BRING PERIODICTABLE FORTHE NEXT SESSION
- 22. (boardwork by group - members Look for the atomic mass of - Hydrogen - Oxygen - Carbon - Sulfur - Potassium - Phosphorus
- 23. Do elements have the same mass? Do compounds have the same mass? ATOMIC MASS – the mass of an individual atom (sum of number of protons and neutrons)
- 24. MOLAR MASS - the mass of one mole of particles (atoms and molecules) - expressed in grams/mole (g/mol)
- 25. Objective: Compute for the molar mass of common substances using the formula (Number of atom A x atomic mass of A) + (Number of atom B x atomic mass of B)….
- 27. Chemical Name Chemical formula Molar Mass (g/mol) Iron (II) sulfate (ferrous sulfate) FeSO4 Ethyl alcohol C2H5OH Ammonia NH3 Citric acid C6H8O6 Aluminum hydroxide Al(OH)3 Molar Mass (g/mol) 151.92 46.08 17.04 176.14 176.14
- 28. A mole of any substance contains Avogadro’s number of representative particles, or 6.022 × 1023 atoms, ions, molecules or formula unit When is a particle classified as an atom, a molecule, or a formula unit?
- 29. Write the correct representative particle (atom , molecule or formula unit) for each of the following. H2O KI O2 Ag Molecule(compound) formula unit (ionic) diatomic molecule Atom( element) I Have NO Bright or Clever Friends
- 30. Formula #1 number of particles = number of moles x Avogadro’s number As the number of moles increases, the number of particles also increases Formula #2 number of moles = mass of the sample / molar mass The number of moles is directly proportional to the given mass and inversely proportional to the molar mass. .
- 31. During exercise, lactic acid (C3H6O3) forms in the muscle causing muscle cramp. If 5.0 g of lactic acid (C3H6O3) concentrate in your leg muscle, how many moles of lactic acid (C3H6O3) are causing you pain? Given: 5.0 g C3H6O3 = mass of the sample Unknown: moles of C3H6O3 number of moles = mass of the sample / molar mass Missing : molar mass Find first the molar mass C3H6O3 3 C x 12.011 = 36.033 6H x 1.008 = 6.048 3 O x 15.999 = 47.997 Total = 90.08 g/mol SOLVE; 5.0 g C3H6O3 mass of sample 90.08 g/mole molar mass = 0.056 mole C3H6O3 is causing leg pain
- 32. Paraffin (C22H46) is a wax used in candle-making during combustion, a 20.0 g candle produces 1.42 moles of CO2. How many molecules of CO2 are released in the atmosphere after using the candle? Given: 1.42 moles of CO2 = number of moles Unknown: number of particles of CO2 FORMULA: number of particles = number of moles x Avogadro’s number = 1.42 moles of CO2 x 6.02x10 23 moles of CO2 = 8.55 x 1023 molécules CO2
- 33. Aspartame (C14H18N2O5) is a synthetic table sugar substitute used in food and drinks. If a food product needs 0.25 g of C14H18N2O5 to sweeten the Queenie cupcake, and you ate this food product, how many molecules of aspartame have you eaten? Given: .25 g C14H18N2O5 - mass of sample Unknown: molecules of C14H18N2O5 Formula: number of particles = number of moles x Avogadro’s number Missing: number of moles (convert first to moles) find the molar mass to convert to moles number of moles = mass of the sample / molar mass.
- 34. How many moles of ascorbic acid does he need to complete the doctor’s prescription of 13.00g of intravenous ascorbic acid everyday for one month? Given: 13 g C6H8O6 - mass of sample per day Unknown : moles Formula number of moles = mass of the sample / molar mass missing: molar mass( get molar mass first) Note: 30 days/month
- 35. You are 50 in your section with 21 boys and 29 girls. If you will be asked what percent of the class are boys and what percent are girls, how are you going to compute for the answer?
- 36. defined as the ratio of the amount of each element to the total amount of individual elements present in the compound multiplied by 100.
- 37. Calculate the percentage composition of Magnesium (Mg) in magnesium carbonate, MgCO3 1Mg x 24.305 g/mole = 24. 305 g/mole 1 C x 12.011 g /mole = 12.011 g/mole 3 O x 15.999 g/mole = 47.997 g/mole Molar mass = 84.313 g/mole 24.305 g/mole 84.313 g/mole = x 100% = 28.83%
- 38. Soil that is already depleted of its nutrients needs fertilizer. One of the nutrients needed to replenish the soil is nitrogen. If you are an agricultural technician helping a farmer, which among these fertilizers are you going to use? a. ammonia (NH3) b. ammonium sulphate (NH4)2SO4 c. ammonium nitrate (NH4NO3)
- 39. Molar mass of NH3 (1N atom x 14.01 g/mole) +( 3 H atom x 1.01 g/mole) =17.04g/mole Molar mass of (NH4)2SO4 (2N atoms x 14.01 g/mole) + (8H atoms x 1.01 g/mole) +(1S atom x 32.07 g/mole) + (4) atoms x 16.00 g/mole) = 112.17 g/mole Molar mass of (NH4NO3) (2N atoms x 14.01 g/mole) + (4H atoms x 1.01 g/mole) +(1S atom x 32.07 g/mole) + (3 O atoms x 16.00 g/mole) = 80.06 g/mole
- 40. 1. What percent of hydrogen (H) is present in water (H2O)? 2. Glucose (C6H12O6) is a six-carbon sugar (hexose) which is also known as the blood sugar. It is an energy source that fuels our body. How many percent of carbon is present in glucose?
- 41. Why is percentage composition important in our daily lives?
- 42. Matter is made up of Which may be Whose amount may be expressed in terms of Whose mass is expressed in equal to MATTER