Physical and Chemical Change Virtual Lab 15 videos_

1) Combination Reactions (A+ B à AB): Two elements (or simple compounds) become one compound. Mg(s) + O,(g) à MgO(s) SO((g) S(s) + O2(g) à 2) Decomposition Reactions (AB à A+ B or ABC à AC + BC): A compound becomes two or more elements (or simpler compounds). Н,О() а Н,(g) + 0,(g) CO,(g) CUCO;(s) à CuO(s) + 3) Single Replacement Reactions (A+ BC à AC + B): An element (a metal or a halogen) replaces another element (metal or halogen) in solution. Zn(s) + CUSO,(aq) à ZnSO̟(aq) + Cu(s) NaBr(aq) à NaClI(aq) + Br,(aq) Cl,(aq) + 4) Double Replacement Reactions (AB + CD à AD + CB): Two elements "switch" (metals replace each other or hydrogen and a metal replace each other). Nal(aq) + Pb(NO,),(aq) à NaNO,(aq) à PbI,(s) NaOH(aq) ӑ H,О() + NaCl{aq) НС(аq) + Reactions may be done in any order. You DO NOT have to indicate the phase(s) of the products. Record observation(s) and write the balanced chemical equation in Table 1. Reaction #1 has been done for you. 1. Using a test tube and dropper…

A piece of alminum foil contains 3.6 x 1021 aluminum atoms.  1) What is the mass of the aluminum foil in grams? 2) The density of aluminum is 2.7 g/cm3. What is the volume of the foil in cm3? 3) Rolls of aluminum foil are 310 mm wide and 0.016 mm thick (height). What length of foil in centimeters contains 3.6 x 1021 aluminum atoms?

Which of the following is a chemical change?   Ice melting to water   Chopping wood for a fire   Sewing a button on a shirt   Wood burning in a fireplace   Pouring water into a glass

What is the correct answer?

In the SI system of units, the mole is one of seven base units. It is frequently used in chemical calculations. However, a mole of something is just a particular quantity of it. It is not a unit of measure in the way that meters, seconds, and kilograms are. Calculations performed with the number of moles of a substance could also be performed with the number of particles of a substance. Based on this information, do you think that the mole should be considered a base unit in the SI system? Explain why or why not.

A chemical reaction (also known as a chemical change) produces substances that are chemically different from the starting materials. An example of a chemical reaction is the formation of water from hydrogen and oxygen gas.In a physical change, a substance changes its physical appearance but not its chemical identity. An example of physical change is the formation of liquid water from solid water, a familiar process called melting. Physically, liquid water looks very different from solid water (ice) but the chemical identity, water, is the same for both. Part A Which of following changes that affect the composition of our atmosphere involve physical changes and which involve chemical reactions? Drag the appropriate items to their respective bins. View Available Hint(s) Reset Help Most of the ozone is created as a byproduct of human-created photochemical smog. Clouds form when water vapor in the air condenses. Carbon monoxide is produced by the combustion of gasoline. Water vapor forms…

4 The mixture used in today's experiment was prepared as a 1:1:1 mixture (by mass) of sand, salt, and salicylic acid. Do your results for the mass of each recovered solid indicate a 1:1:1 composition of the mixture? Explain your response.

Why do physical properties play a role in chemistry if they do not involve any chemical changes?

Read the descriptions below of two substances and an experiment on each. Decide whether the result of the experiment tells you the substance is a pure substance or a mixture, if you can. • Sample A is 100. g of a coarse grey powder with a faint unpleasant smell. 15. g of the powder is put into a funnel lined with a sheet of thick paper. Distilled water is poured slowly over the powder. All of the powder disappears, and the water under the funnel turns a deep purple. • Sample B is a solid yellow cube with a total mass of 50.0 g. The cube is ground to a fine orange powder and added to a 500 mL beaker full of water. The beaker is stirred vigorously. Some of orange powder settles to the bottom of the beaker, and some rises to the top and floats on the water. When the powder at both the bottom and the top of the beaker is filtered out, dried, and weighed, the total mass is measured to be 50.1 g. pure substance Is sample A made from a pure substance or a mixture? If the description of the…

Classify the following materials as substances or mixtures: absolute (pure) alcohol, milk (as purchased in a store), copper wire, rust, barium bromide, concrete, baking soda, and baking powder. If they are mixtures, subclassify them as homogeneous or heterogeneous; if they are substances,subclassify them as compounds or elements.