Lightsticks or glowsticks are used by divers, campers, and for decoration and fun. A lightstick is a plastic tube with a glass vial inside it. To activate a lightstick, you bend the plastic stick, which breaks the glass vial. This allows the chemicals that are inside the glass to mix with the chemicals in the plastic tube. These two chemicals react and release energy. Another part of a lightstick is a fluorescent dye which changes this energy into light, causing the lightstick to glow!
Endothermic and exothermic reactions
In each of the following reactions, say whether the reaction is endothermic or exothermic, and give a reason for your answer.
H = -802 kJ.mol
The following reaction takes place in a flask:
Within a few minutes, the temperature of the flask drops by approximately 20C.
H = -411 kJ
For each of the following descriptions, say whether the process is endothermic or exothermic and give a reason for your answer.
evaporation
the combustion reaction in a car engine
bomb explosions
melting ice
digestion of food
condensation
Spontaneous and non-spontaneous reactions
Demonstration : spontaneous and non-spontaneous reactions
Apparatus and materials:
A length of magnesium ribbon, thick copper wire and a bunsen burner.
Method:
Scrape the length of magnesium ribbon and copper wire clean.
Heat each piece of metal over the bunsen burner, in a non-luminous flame. Do Not look directly at the flame. Observe whether any chemical reaction takes place.
Remove the metals from the flame and observe whether the reaction stops. If the reaction stops, return the metal to the bunsen flame and continue to heat it.
Results:
Did any reaction take place before the metals were heated?
Did either of the reactions continue after they were removed from the flame?
Write a balanced equation for each of the chemical reactions that takes place.
In the demonstration above, the reaction between magnesium and oxygen, and the reaction between copper and oxygen are both
non-spontaneous . Before the metals were held over the bunsen burner, no reaction was observed. They need energy to
initiate the reaction. After the reaction has started, it may then carry on spontaneously. This is what happened when the magnesium reacted with oxygen. Even after the magnesium was removed from the flame, the reaction continued. Other reactions will not carry on unless there is a constant addition of energy. This was the case when copper reacted with oxygen. As soon as the copper was removed from the flame, the reaction stopped.
Now try carefuly adding a solution of dilute sulfuric acid to a solution of sodium hydroxide. What do you observe? This is an example of a
spontaneous reaction because the reaction takes place without any energy being added.
Spontaneous reaction
A spontaneous reaction is a physical or chemical change that occurs without the addition of energy.
Activation energy and the activated complex
From the demonstrations of spontaneous and non-spontaneous reactions, it should be clear that most reactions will not take place until the system has some minimum amount of energy added to it. This energy is called the
activation energy .
Activation energy is the 'threshold energy' or the energy that must be overcome in order for a chemical reaction to occur.
Communication is effective because it allows individuals to share ideas, thoughts, and information with others.
effective communication can lead to improved outcomes in various settings, including personal relationships, business environments, and educational settings. By communicating effectively, individuals can negotiate effectively, solve problems collaboratively, and work towards common goals.
it starts up serve and return practice/assessments.it helps find voice talking therapy also assessments through relaxed conversation.
miss
Every time someone flushes a toilet in the apartment building, the person begins to jumb back automatically after hearing the flush, before the water temperature changes. Identify the types of learning, if it is classical conditioning identify the NS, UCS, CS and CR. If it is operant conditioning, identify the type of consequence positive reinforcement, negative reinforcement or punishment
nature is an hereditary factor while nurture is an environmental factor which constitute an individual personality. so if an individual's parent has a deviant behavior and was also brought up in an deviant environment, observation of the behavior and the inborn trait we make the individual deviant.
Samuel
I am taking this course because I am hoping that I could somehow learn more about my chosen field of interest and due to the fact that being a PsyD really ignites my passion as an individual the more I hope to learn about developing and literally explore the complexity of my critical thinking skills
hello. autism is a umbrella term. autistic kids have different disorder overlapping. for example. a kid may show symptoms of ADHD and also learning disabilities.
before treatment please make sure the kid doesn't have physical disabilities like hearing..vision..speech problem. sometimes these
Jharna
continue..
sometimes due to these physical problems..the diagnosis may be misdiagnosed.
treatment for autism.
well it depends on the severity.
since autistic kids have problems in communicating and adopting to the environment.. it's best to expose the child in situations where the child
Jharna
child interact with other kids under doc supervision.
play therapy.
speech therapy.
Engaging in different activities that activate most parts of the brain.. like drawing..painting. matching color board game.
string and beads game.
the more you interact with the child the more effective
Jharna
results you'll get..
please consult a therapist to know what suits best on your child.
and last as a parent. I know sometimes it's overwhelming to guide a special kid.
but trust the process and be strong and patient as a parent.
Jharna
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