Chem 111, Week 1 Notes
Chem 111, Week 1 Notes Chem 111-007
Popular in Principles of Chemistry I
verified elite notetaker
Popular in Chemistry
This 8 page Class Notes was uploaded by je on Saturday September 10, 2016. The Class Notes belongs to Chem 111-007 at University of Northern Colorado taught by Corina Brown in Fall 2016. Since its upload, it has received 3 views. For similar materials see Principles of Chemistry I in Chemistry at University of Northern Colorado.
Reviews for Chem 111, Week 1 Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/10/16
August 22, 2016 Chapter 1: Introduction Matter & Measurement Chemistry is the study of matter and its changes. o Macroscopic (observable) level o Sub-microscopic (particulate) level Matter – anything with mass and volume Mass – amount of substance in an object Weight – measures the gravitational pull Volume – amount of space taken by an object Density – mass (g) divided by volume (cm ) m=18.96g d=18.96g/4.31cm^3 3 3 V=4.31cm d=4.39g/cm August 24, 2016 Classification of Matter (composition) Matter Pure Substance Mixture of Pure Substance Element Compound Homogeneous Heterogeneous Pure Substance Constant composition Element – made of the same kind of atoms Molecules – 2 or more elements combined Compounds – 2 or more elements chemically combined Mixture – physical combination of two or more (composition varies) Homogeneous – uniform composition o Ex: saline solution Heterogeneous – non-uniform composition o Ex: salt and paper Seawater Homogenous mixture Helium Gas Element Sodium Chloride Compound Bottle of Soft Drink Homogenous Mixture Milkshake Homogeneous Mixture Air in a Bottle Homogeneous Mixture Concrete Heterogeneous Mixture Classification of Matter (state) Solid – has a definite shape and volume Liquid – has a definite volume, but has no definite shape Gas – has no definite shape or volume Properties & Changes of Matter Properties Physical Changes – can be observed without changing the identity of the substance o Ex: density, boiling point, mass, volume Chemical Changes – describes the ability of a substance to combine with or change into one or more substances o Ex: flammability, corrosiveness, reactivity with acid, gas formation Ironing Physical Rusting Nails Chemical Fireworks Chemical Frying an Egg Chemical Ice Melting Physical Bread with Butter Physical Types of Changes Physical – do not change the composition of a substance o Ex: changes in state, temperature, volume, etc. Chemical – changes result in new substance o Ex: combustion, oxidation, decomposition, etc. Types of Properties Intensive – does not depend on amount of substance present o Ex: density, boiling point, color, etc. 2 Extensive – does depend on the amount of substance present o Ex: mass, volume, energy Physical/Chemical Properties 1 Ice water has a temperature of 0°C, water boils at 100°C. Physical. 2 Silver tarnish due to its ability to combine with sulfur. Chemical. 3 Nitroglycerine explodes. Chemical. 4 Acids are sour; bases are bitter. Physical. 5 Copper conducts electricity; diamond doesn’t. Physical. 6 Neon because it does not react to anything. Chemical. Separation of Mixtures (Lab information) Physical means it can be used to separate a mixture into its pure components. o Magnet o Filtration – solid substances are separated from liquids and solutions. Distillation uses differences in the boiling points of substances to separate a homogeneous mixture into its components. Chromatography – this technique separates substances on the basis of differnces in solubility in a solvent. Mass kg 1kg=1000g length m 1km=1000m 1g=1000mg 1m=100cm 1mg=1000µg 1m=1000mm 1kg=2.2lbs 3 L x L = Area L x L x L = Volume Convert 1.5km to m Convert 15dL to L 1.5km x 1000m = 1500m 15dL x 1 L = 1.5L 1km 10dL 4 August 26, 2016 Application – Displacement Method m=12.0g d = m/v V initial = 10mL V = 16mL-10mL d = 12g/6mL V final = 16mL V = 6mL d = 2g/mL Heat vs. Temperature Heat : energy that is transferred from hotter objects to cooler objects Temperature : the average kinetic energy of a sample o Kelvin is the SI temperature scale o Celsius and Kelvin scales are most often used o Fahrenheit scale is not used in scientific measurements 0°C = 273K = 32°F K = °C + 273.15 °F = (9/5)(°C)+32 °C = (5/9)(°F – 32) 1. 25°C to K K = 25°C + 273.15 K = 298.15 2. 273K to °C 273K = °C + 273.15K °C = 0 or -.15 3. 179.2°F to °C °C = (5/9)(179.2 – 32) °C = 81.78°C Uncertainty in Measurements The uncertainty in measurement is determined by the measuring device Measurements Every measurement carries a degree of uncertainty or error Exact Number o Has a number that is known exactly Inexact numbers o Depend on how they are determined o Scientific instruments have limitations Accuracy vs. Precision Accuracy o Refers to the closeness of a measurement to the true value of the quantity Precision o Refers to the closeness of several measurements to each other Significant Figures (Sig Figs) Sig Figs are the number of digits that are known to be accurate plus one more The number of sig figs is determined by the measuring device Sig Fig Rules 1. All digits from 1 through 9 are significant 2. Zeroes between two sig figs are significant 3. Zeroes at the beginning of a number are never significant 4. Zeros at the end of a number are significant if a decimal point is written after the number 5. When a number ends with zeros but contains no decimal point, zeroes are not significant 2 There are practice problems on the worksheet handed out in class today. 3
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'