Section Assessment (pag 88)

BASICS AND ACIDICS

1. Drain cleaner, pH 13
2. Milk of magnesia, pH 10.5
3. Baking soda, pH 9
4. Seawater, pH 8
5. Tomato juice, pH 5
6. Lemon juice, pH 2

          (from most basic to most acidic)

PH

PH 

 1. What is PH?

2.What are PH values?

Do these values depend on something?  Explain your answers.

3. Check Chart 3.2 about acids and bases.

4. What is Neutralization?  Give examples.What can you explain about it?

  

ANSWERS

1.In chemistry, pH (/piːˈ(h)eɪtʃ/) (potential of hydrogen) is a numeric scale used to specify the acidity or basicity of an aqueous solution. It is approximately the negative of the base 10 logarithm of the molar concentration, measured in units of moles per liter, of hydrogen ions. More precisely it is the negative of the logarithm to base 10 of the activity of the hydrogen ion.^[1] Solutions with a pH less than 7 are acidic and solutions with a pH greater than 7 are basic. Pure water is neutral, at pH 7 (25°C), being neither an acid nor a base. Contrary to popular belief, the pH value can be less than 0 or greater than 14 for very strong acids and bases respectively.^[2]

2. The pH scale is theoretically open-ended but most pH values are in the range from 0 to 14.An acid is a substance that donates hydrogen ions. A base is a substance that accepts hydrogen ions. The acid solutions have lower PH values. The basic solutions have higher PH values.

3. 
All acids and bases do not ionize or dissociate to the same extent. This leads to the statement that acids and bases are not all of equal strength in producing H+ and OH- ions in solution. The terms "strong" and "weak" give an indication of the strength of an acid or base. The terms strong and weak describe the ability of acid and base solutions to conduct electricity. If the acid or base conducts electricity strongly, it is a strong acid or base. If the acid or base conducts electricity weakly, it is a weak acid or base.

4.In chemistry, neutralization is a chemical reaction in which an acid and a base react quantitatively with each other. In a reaction in water, neutralization results in there being no excess of hydrogen or hydroxide ions present in the solution. The pH of the neutralized solution depends on the acid strength of the reactants. Neutralization is used in many applications.In the context of a chemical reaction the term neutralization is used for a reaction between an acid and a [alkaline (chemistry)|base]] or alkali. Historically, this reaction was represented as

acid + base → salt + water

For example:

HCl + NaOH → NaCl + H₂O

Section Assessment (pag.80)

SKILL ACTIVITY                                                                                                                                                                                         The dependent variable is dependent on the independent variable, and the independent variable is independent of the others. Control variables are controlled to make sure that the independent variable is the only factor causing a change in the dependent variable. Plant growth is likely affected by fertilizer (making it dependent), but fertilizer application is not affected by plant growth (making it independent). The amount of sunlight can affect growth rate, so it's controlled to stay the same in each experiment.                                                                                                                                                                             Let's look at a few different experiments to get a better idea of how these variables work. Say, for example, that you wanted to look deeper into that question you had earlier about fishing. The experiment you run depends entirely on the question you ask.

To start, you might ask, 'When is the best time of day to catch fish?' From past experiences, you hypothesize that fish are more active in the morning; therefore, this is the best time of day to catch fish. In your experiment, the time of day is the independent variable because this is what you change in the experiment. Dependent on this is the number of fish you catch, so this would be your dependent variable.

For this experiment, you will need to control for many factors, so you will have several different control variables. First, you need to make sure that you use the same equipment to catch fish each time. If you used different lures each time you went out, you would have no idea if the number of fish you caught was related to the time of day or the lure you used because both variables changed. This makes the fishing equipment one control variable.                                                   

Section Assessment Item4

COMPARING  AND CONTRASTING

Helium-neon laser:a helium–neon laser or HeNe laser, is a type of gas laser whose gain medium consists of a mixture of 85% helium and 15% neon inside of a small bore capillary tube, usually excited by a DC electrical discharge. The best-known and most widely used HeNe laser operates at a wavelength of 632.8 nm, in the red part of the visible spectrum. (GAS)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  Cloudy Ice Cubes:The main reason is that the (hopefully) crystal-clear water you pour into the ice trays is not as pure as it seems, containing small amounts of (hopefully) harmless suspended minerals and sediment.

Because all objects freeze from the outside in, the center of the cube is the last to solidify. Water free of minerals and impurities freezes first, pushing the cloudy parts containing the sediment (and tiny trapped air bubbles) toward the center. The result is a harmless (but not particularly photogenic) ice cube clouding.

Not only do ice cubes cloud in the freezer, but they also shrink noticeably after about a week or two due to sublimation, the term used for evaporation directly from the solid to gas phase.                                                                                                                                                                                                                                                                                                      Bronze:Bronze is an alloy consisting primarily of copper, commonly with about 12% tin and often with the addition of other metals (such as aluminium, manganese, nickel or zinc) and sometimes non-metals or metalloids such as arsenic, phosphorus or silicon. These additions produce a range of alloys that may be harder than copper alone, or have other useful properties, such as stiffness, ductility, or machinability.                                                                                                                                                                                                                                                                                                                                                  Ginger Ale: Ginger ale commonly contains carbonated water, sugar or HFCS, and artificial or natural ginger-flavour.(GAS)                                                                                                                                                                                                                                                                                                                COMPARE: All three solutions are gas except Bronze that is a solid.                                                             CONTRASTING :Ginger ale is a liquid gas but helium-neon laser is a gas, gas. Cloudy ice cubes is a solid,gas but Bronze is a solid.

Section Assessment

Skill Builder            https://drive.google.com/open?id=0B6Tt0hc92TfWMEFLUE9RSF9NMk0   

Skill Builder

When Gregor Mendel began his investigations of plant genetics in the 1800s, he worked alone — a middle-aged European monk counting peas in the abbey garden. One hundred and fifty years later, modern plant genetics laboratories, like Chelsea Specht's below, look a lot more diverse and employ the latest DNA sequencing techniques. When J.J. Thomson discovered a new particle of matter — the electron — at the turn of the century, his lab equipment mainly consisted of vacuum tubes, magnets, and some simple wiring. One hundred years later, scientists searching for new particles like the Higgs boson use a supercollider — a 17-mile-long machine that costs several billion dollars and will produce data to be analyzed by the most powerful supercomputer in the world. Science has come a long way in the last 150 years! We now have more powerful data analysis techniques, more sophisticated equipment for making observations and running experiments, and a much greater breadth and depth of scientific knowledge. And as the attitudes of the broader society have progressed, science has benefited from the expanding diversity of perspectives offered by its participants.

What is Energy? & Types of Energy

Energy                                                  Types of Energy

What is Energy?                                  Kinetic & Potencial Energy are the main formes of energy.                                                                       Kinetic Energy is for exemple: feel the air around you that is                                                                    kinetic energy  that's because it is moving.                                    

                                                                Potencial energy is the energy stored inside an obbject

                                                                 If an object is not moving and it's stild it mean's that is has 

                                                                 potencial energy in it. It is not to have potencial energy                                                                            because if it released it would do a lot of work.

                                                                 Energy can neither be destroyed nor created but it can                                                                              transform from one form of energy to another.

                                                                 If an object has potential and kinetic energy it is none as a                                                                      mechanical energy.

                                                                 

                                                                              

Energy is ability to do some work.            

 All things need energy to move.

Energy can be stored.

Cars use petrol or gas as a energy.

When you write you use a lot of force.

You also use so much muscular energy.

In the world their is heat enegy.

Also their is solar energy , hydel energy.

Wind energy , electrical energy .

Muscular energy .