Chem 110 Past Lecture Slides PDF

Chem 110 Thought for the day Neon doesn’t doesn’t have any chemistry on stage. You could say it’s a bad reactor  Put name here Quiz 4...

Chem 110 Thought for the day Neon doesn’t doesn’t have any chemistry on stage. You could say it’s a bad reactor  Put name here Quiz 4 Please format (don’t forget sig figs) card horizontally A solution of Vinegar is 4.00 % acetic acid by weight and its density is 1.049 g/ml. How many grams of acetic acid are in 250.0 ml of this solution.  Put name here Quiz 4 Please format (don’t forget sig figs) card horizontally A solution of Vinegar is 4.00 % acetic acid by weight and its density is 1.049 g/ml. How many grams of acetic acid are in 250.0 ml of this solution. 250 ml = 250 ml 1.049 g = 1 ml 250 ml 1.049 g 4 parts = 1 ml 100 parts = 10.49 g rounding to 3 sig figs 10.5 MATH Review ForCHEM110 Need help with Math background for CHEM? Drop-In Workshop: Wednesday Jan 22, Room 216 12:15 1:15 (also available via Zoom – email for details) Light refreshments Included ! Open to all Students Questions? Email Prof. Musolino, [email protected] Chem 110 Reminders: Cell phones Participation points Chapter Goals for the day 1. States of matter 2. Daltons postulates 3. Chemical and physical properties 4. Mixtures/substances, compounds and elements 5. Measurements in chemistry 1. SI units 2. Uncertainty and measurements 3. Use of exponents 4. Dimensional analysis 6. Calculating a percentage 7. Density and specific gravity 8. Heat-Temperature and Heat Transfer 6 Chapter 2 Goals 6. Formula Weights, Molecular 1. Chemical Formulas Weights, and Moles 2. Ions and Ionic 7. Percent Composition and Compounds Formulas of Compounds 3. Names and (Chapter 8. Derivation of Formulas from Elemental Composition 6?) Formulas of Some Ionic 9. Determination of Molecular Formulas Compounds 10. Some Other Interpretations of 4. Atomic Weights Chemical Formulas 5. The Mole 11. Purity of Samples 7 Density and Specific Gravity What is weight What is mass What is density? density = mass/volume Volume =cm3 = ml Why does ice float in liquid water? It is less dense than water. 8 Density and Specific Gravity Example 1-6: Calculate the density of a substance if 742 grams of it occupies 97.3 cm3. We have the mass We have the volume 742 g /97.3 cm3 = 7.63 g/cm3 9 Density and Specific Gravity Example 1-7: Suppose you need 125 g of a corrosive liquid for a reaction. What volume do you need? (liquid’s density = 1.32 g/mL) We know the mass in g so we are converting to volume this means we invert the density to get volume on top 125g (1 ml/1.32g)=94.7ml 10 Density and Specific Gravity g/cm3 g/cm3 Water’s density is essentially 1.00 g/ml at room T. Thus the specific gravity of a substance is very nearly equal to its density. Specific gravity has no units. 11 Density and Specific Gravity Example 1-8: A 31.0 gram piece of chromium is dropped into a graduated cylinder that contains 5.00 mL of water. The water level rises to 9.32 mL. What is the specific gravity of chromium? 12 Density and Specific Gravity Example 1-8: A 31.0 gram piece of chromium is dropped into a graduated cylinder that contains 5.00 mL of water. The water level rises to 9.32 mL. What is the specific gravity of chromium? Volume = Vf–Vi = 9.32 – 5 = 4.32 ml = 4.32 cm3 Density Mass/Volume = (31.0 g /4.32 cm3)/1.00g/cm3 = 7.1759 or 7.18 = specific gravity of Chromium 13 Density and Specific Gravity Example 1-9: A concentrated hydrochloric acid solution is 36.31% HCl and 63.69% water by mass. The specific gravity of the solution is 1.185. What mass of pure HCl is contained in 175 mL of this solution? 175 ml x 1.185 x(1.00g/1.00ml) (36.31/100.0)=75.3g density of water 14 Heat and Temperature Heat and Temperature are not the same thing Heat is the ability to do work T is a measure of the intensity of heat in a body T will determine the direction of flow from hotter to colder 3 common temperature scales - all use water as a reference 15 Heat and Temperature MP water BP water Fahrenheit 32.00 oF 212.0 oF Celsius 0.000 oC 100.0 oC Kelvin 273.15 K 373.15 K 16 Relationships of the Three Temperature Scales Fahrenheit and Centigrade relationships ◦ C = (◦F – 32)*5/9 ◦ F = ◦C *9/5 +32 I will not ask you to do this but its useful to know 17 Relationships of the Three Temperature Scales Centigrade and Fahrenheit relationships K = ◦C + 273.15 ◦ C = K – 273.15 This you need to know and should know by