Isa Science Blog
viernes, 29 de septiembre de 2017
SKILL BUILDER PAGE 88
ACIDIC AND BASIC
https://drive.google.com/open?id=0B7iv3aqF9aB_TEkyc21qU2MzSEk
miércoles, 27 de septiembre de 2017
PH
1. What is PH?
A/ PH is measure of how acids or
basic solution is, related to its concentration of hydronium ions and hydroxide
ions.
2. What are PH values? Do these
values depend on something? Explain your
answers.
A/ The pH scale generally ranges
from 0 to 14. more acidic solutions have lower pH values , and a solution with
a pH of 0 is highly acids. A solution that has a PH of 7 is neutral. More basic
solutions have higher pH values, and a solutions with a pH of 14 is
extremely basic.
The acid solutions have more
hydronium ions than hydroxide ions.
Neutral solutions have equal numbers of two ions. Basic solutions have
more hydroxide ions than hydronium ions.
3. Check Chart 3.2 about acids
and bases. What can you explain about
it?
A/ The strong acids are:
Hydrochloric - Sulfuric - Nitric.
The strong bases are: Sodium hydroxide
- Potassium hydroxide.
The weak acids are: Acetic -
Carbonic – Ascorbic.
The weak bases are: Ammonia - Aluminum
hydroxide - Iron (||) hydroxide.
4. What is Neutralization? Give examples.
A/ is the interaction that occurs
between acids and bases in which the
properties of each are canceled out by th other.
Example :
1: an acid (substances releasing hydrogen ions
H), and a base (subtance that releases OH ions) react to form a salt and water.
2: the pH of the neutralization
reaction is a neutral ie 7, and the temperature increases ligemene as the
reaction occurs.
martes, 26 de septiembre de 2017
SKILL BUILDER PAG 80
VARIABLES AND
CONTROLS
How did dissolving salt in one
beaker affect the water temperature?
Dissolving common salt in
water is a process that is not energetically neutral. It ‘takes the electrical
energy to break the red salt crystal and the hydrogen bonds between the water
molecules. At room temperature, the result is such that the entire process absorbs
the energy; the enthalpy of the dissolution of the common salt in water is ΔH ≈
3.9 kJ mol-1.
The agitation of the water
causes an increase in temperature due to the increase of kinetic energy,
however, the dissolution of the salt consumes part of the energy generated, so
that the temperature of the salt solution is lower than the water alone.
What were the
controls? Variables?
The independent variable is the factor that a scientist
manipulates to obtain results.
The dependent variable will respond to changes in the
independent variable.
Control variables are the things that are kept constant
in each test of the experiment.
In this case the independent variable is the dissolution
of the salt in water, the dependent variable is the temperature of the water
that will change due to the presence of the salt. The control variable is the
amount of water added, which is the same from the beginning to the end of the
experiment in both beakers.
PRACTICING THE SKILL
1. Ten
grams of sugar dissolves more quickly in a liter of pure,hot,tap wáter tan it
does in a liter of pure,cold,tap wáter. List the controls, the independent
variable, and the dependent variable.
Controls: Same amount of water, same
amount of sugar, both containers are covered.
Independent variables: water
temperatures: cold and hot.
Dependent variables: time in which the
sugar dissolves.
2. Identify
the dependent variable from the following hypothesis: Of Premium gasoline is
more efficient, so it should increase the fuel mileage of our family car.
Dependent variable: family car
efficiency
viernes, 22 de septiembre de 2017
SKILL BUILDER, page 74. COMPARING AND CONTRASTING
COMPARING
|
CONTRASTING
|
The mixtures studied are homogeneous, except for cloudy ice cubes
with a heterogeneous appearance because the outside of the cube is the first
to freeze, and the interior of the water to find its liquid state.
In alloys, carbonated-beverage and lasers are not distinguished
phases, so they can be considered homogeneous.
|
The mixtures analyzed are of different composition in the state in
which they are, the helium-neon laser is a gaseous mixture, because the
elements are in this state.
Alloys are solid mixtures (copper-tin), their appearance is totally
homogeneous.
Ice cubes are liquid-solid mixtures, due to the presence of small
particles (corresponding to minerals) found in water.
Ginger ale is a carbonated-beverage, so it has a gaseous part and a
drink, usually the gas is dissolved in the liquid part, when the solution is
in contact with the environment, ie the bottle, the gas escapes from the
liquid.
|
viernes, 15 de septiembre de 2017
viernes, 8 de septiembre de 2017
lunes, 21 de agosto de 2017
Energy and types of Energy
Energy is the ability to do some work.We know also that all things around us need energy to move. When we apply a force onto an object, we are using our muscular energy. There are several types of energy, depending on where they come from: The first one is electrical energy, an example of it is our light bulbs, the tv or the air conditioners we use at home. The second one is heat energy, coming from fire(as an example) or the 90% of the electrical energy that become heat energy in our light bulbs(that's why they are warm when we touch them). When we move objects with our hands, we use our muscles, so it is called: muscular energy! If we imagine we are doing some sport at the park and it is very sunny, we can understand how Solar Energy does affect us, and how they can be stored into solar panels. The last two types of energy are: hydel energy, coming from moving water and wind energy(come from moving air and obtained with windmills).
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