CHE 106 Lecture Notes - Lecture 4: Chemical Property, Physical Property, Combustibility And Flammability

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CHE 106 Lecture Notes - Lecture 3: Significant Figures, Scientific Notation

CHE 106 Lecture Notes - Lecture 4: Chemical Property, Physical Property, Combustibility And Flammability

CHE 106 Lecture Notes - Lecture 5: Significant Figures, Dimensional Analysis, Scientific Notation

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Chemistry refers to the study of composition, structure and properties of matter and energy. Matter: this is a substance that has mass and occupies space. Matter is typically classified in two major ways: physical state (solid, liquid or gas, composition (element, compound or mixture) also known as the chemical constitution. A gas/vapor: has no fixed volume or fixed shape. It uniformly fills its container and can be compressed to occupy a smaller volume. A liquid: has a distinct volume but no fixed shape. Thus, it takes the shape of its container. A solid: has a fixed volume and a fixed shape. Note: changes in temperature or pressure causes the conversion from one physical state to another. In a gas, the molecules are far apart and moving at high speeds, colliding repeatedly with one another and with the walls of the container.

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I need help doing my lab homework, I missed lab that day because, I was sick and it's due.

Chemical Reactions and Equations Learning objectives To observe physical and chemical properties associated with chemical changes To be able to give evidence for the occurrence of a chemical reaction To write a balanced chemical equation To identify areaction as a combination, decomposition, precipitation, single or double replacement, or combustion reaction ntroduction When a substance undergoes a physical change, it changes its appearance but not its composition. For example, when ice melts to form water, it undergoes a physical change from solid to liquid. In a chemical change, the composition of a substance is changed to give a new substance with different physical and chemical properties. For example, when silver tarnishes, the shiny silver (Ag) changes to a dull gray silver sulfide (AgaS). Not only has the chemical formula changed from Ag to Agus, but also the physical properties (shininess) of the substance have changed. Some examples of physical and chemical changes are listed in Table 1 below. Table 1. Comparison of Physical and Chemical Changes Examples of Physical changes Examples and Evidence of Chemical Changes Change in state (melting, freezing, evaporating Formation of a gas (bubbles) subliming) Formation of a solid (precipitate) Change in size Tearing Change in Color Heat is given off or absorbed A solid dissolving in a solvent In a chemical reaction, atoms in the reactants are rearranged to produce new combinations of atoms in the products. However, the total number of atoms of each element in the reactants is equal to the total number of atoms in the products. This is true according to the Law of Conservation of Mass, which states that the total mass remains constant during a chemical reaction. In other words, matter cannot be created or destroyed in a chemical reaction. In a chemical equation, the reactants are shown on the left and the products are on the right. An arrow in between indicates that a chemical reaction occurs. Finally, the physical state of each compound is designated in parentheses after the chemical formula. Solid, liquid, gas, and aqueous (dissolved in water) are shown as(s,(n,(g), and (aq), respectively.

1. Which characteristic below describes ONLY a solid (not liquid or gas)?
a) definite shape b) particles in contact c) definite volume d) completely fills container
2. When iron rusts, it forms a reddish-brown solid. This is:
a) a physical change b) a chemical change c) no change at all
3. What is the name of FeSO4?
a) iron (I) sulfate b) iron (II) sulfate c) iron sulfite d) iron sulfide
4. A bottle label states that the bottle contains âdrinking water with minerals added for flavor. This would be an example of:
a) an element b) a compound c) a heterogeneous mixture d) a homogeneous mixture
5. Which answer has the correct number of significant figures for: length = 2.0 m + 0.2100 m?
a) 2.2 b) 2.21 c) 2.210 d) 2.2100
Place the answer with the correct number of significant figures on the lines provided below.
6. To drive one kilometer, how many centimeters should you drive?
_______________cm
7. A 10.0 gram block of gold has a density of 19.32 g/cm3. What is its volume?
______________cm3
8. What is the formula of sodium sulfide?
_________________________
9. What is the name of H2S?
_______________mm
10. How many neutrons are in 35Cl?
_______________ neutrons
For problems 11 through 13, show your work to receive full credit and use the correct number of significant figures in your final answer.
11. The density of nickel is 8.91 g/cm3. Calculate the mass of a nickel ball with a radius of 0.50 mm in grams.
(Ï = 3.1416; Vsphere = 4Ïr3/3)
12. The recommended adult dose of Elixophyllin , a drug used to treat asthma, is 6.00 mg/kg of body mass. Calculate the dose in milligrams for a 134-lb person.
13. It is 273 K outside. Do you need a jacket? Why or why not? (show your work for full credit)
14) Element X has three naturally occurring isotopes. The masses (amu) and % abundances of the isotopes are given in the table below. What is the average atomic mass of the element in amu?

isotope38 abundance of 5.07,mass of 37.919

isotope39x,abundance of 15.35,mass of 39.017

isotope 42,abundance of 79.85,mass of 42.111

15. Classify each of the following elements as alkali, alkaline earth, halogen or a noble gas:
a) He ________________________
b) F ________________________
c) Na ________________________
d) Ca ________________________
e) Br ________________________

Need help answering the pre - lab questions

Chemistry 1010 Laboratory Fall 2016 Lab: Percent Sugar Content of Beverages ave you ever been to the ocean? Does it seem that you can float or swim much easier in the ocean than in a swimming pool? Seawater is more dense than freshwater due to the presence of dissolved salt in the cean As a result, our buoyancy-ability to float-is greater in salt water than in plain water. What factors of a particular substance is dissolved in it? Background The density of a pure substance is a characteristic physical property that can be used to identify the substance does not depend on the amount of the substance. The density of any material is determined by measuring its mass and volume and then dividing the mass by the volume. The mass of a substance can be measured directly using a balance. The volume of a liquid can be measured directly using special laboratory glassware, such as a graduated cylinder, buret, or pipet. In this experiment, liquild volumes will be measured using a graduated cylinder Density is defined as the ratio of mass per unit volume. It is an "intensive" property, that is, it The density of a solution depends on its concentration, that is, how much solid is dissolved in the liquid. The higher the concentration of solid, the greater the density of the solution. A convenient way to express concentration is in units of weight percent, which corresponds to the number of grams of sollid that are present in 100 g of solution. A 20% salt solution is prepared by dissolving 20 g of sodium chloride (table salt) in 80 g of water to give a final mass of 100 g of solution. When the density of a solution is plotted on a graph against the concentration of the solution, a regular pattern becomes evident, specifically that density is directly proportional to the concentration of solid in the solution. A 20% salt solution, for example, has a higher density and higher concentration of solid than a 10% salt solution. If the densities of several solutions of known concentration are determined experimentally and plotted on a graph, a calibration curve can be drawn to show a straight-line relationship between the density of a solution and the concentration of solid (note: the calibration curve in this lab reveals a linear (straight-line) relationship, but not all calibration curves are linear). The calibration curve can then be used to find the concentration of solid in an unknown solution simply based on experimentally measuring the density of the solution. Experiment Overview The purpose of this experiment is to determine the percent sugar content in beverages. The density of five reference" solutions will be determined in Part A. The reference solutions contain known amounts sugar " of sugar (0-20%). Their densities will be plotted on a graph to obtain a calibration curve of density versus nt sugar concentration. In Part 8, the densities of two beverages will also be determined, and the The results will be compared against the information provided on the nutrition labels for these beverages 1. if the following mass and volume data are used to calculate the density of solution, how many cal libration curve, created from the data in Part A, will be used to find the percentage of sugar they contain. Pre-Lab Questions significant figures are allowed in the calculated density? Mass of solution 12.53 g: volume of solution = 8.27 mL Calculate the density of the solution described in Question #1 (Hint: This is a 2-step problem. Then calculate the percent sugar in the beverage.) According to its nutrition label, orange soda 2. 3. First, use the density to convert the 355-mL serving size to grams. Lab: Percent Sugar Content of Beverages

CHE 106 Lecture Notes - Lecture 4: Chemical Property, Physical Property, Combustibility And Flammability

CHE 106 Lecture Notes - Lecture 3: Significant Figures, Scientific Notation

CHE 106 Lecture Notes - Lecture 4: Chemical Property, Physical Property, Combustibility And Flammability

CHE 106 Lecture Notes - Lecture 5: Significant Figures, Dimensional Analysis, Scientific Notation

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