During the first heating of mercury (II) oxide, the only change that took place was a change in colour from orange-red to black and then back to its original colour.
When the test tube was heated again, deposits of mercury formed on the inner surface of the test tube. What colour is this mercury?
The glowing splinter burst into flame when it was placed in the test tube, meaning that oxygen is present.
Conclusions
When mercury oxide is heated, it decomposes to form mercury and oxygen. The chemical decomposition reaction that takes place can be written as follows:
2HgO
2Hg
O
2
Synthesis reactions
During a
synthesis reaction , a new product is formed from elements or smaller compounds. The generalised equation for a synthesis reaction is as follows:
A + B
AB
One example of a synthesis reaction is the burning of magnesium in oxygen to form magnesium oxide(
[link] ). The equation for the reaction is:
2Mg + O
2
2MgO
Experiment: chemical reactions involving iron and sulphur
Aim
To demonstrate the synthesis of iron sulphide from iron and sulphur.
Apparatus
5,6 g iron filings and 3,2 g powdered sulphur; porcelain dish; test tube; Bunsen burner
Method
Measure the quantity of iron and sulphur that you need and mix them in a porcelain dish.
Take some of this mixture and place it in the test tube. The test tube should be about 1/3 full.
This reaction should ideally take place in a fume cupboard. Heat the test tube containing the mixture over the Bunsen burner. Increase the heat if no reaction takes place. Once the reaction begins, you will need to remove the test tube from the flame. Record your observations.
Wait for the product to cool before breaking the test tube with a hammer. Make sure that the test tube is rolled in paper before you do this, otherwise the glass will shatter everywhere and you may be hurt.
What does the product look like? Does it look anything like the original reactants? Does it have any of the properties of the reactants (e.g. the magnetism of iron)?
Results
After you removed the test tube from the flame, the mixture glowed a bright red colour. The reaction is exothermic and
produces energy .
The product, iron sulphide, is a dark colour and does not share any of the properties of the original reactants. It is an entirely new product.
Conclusions
A synthesis reaction has taken place. The equation for the reaction is:
Fe + S
FeS
Investigation : physical or chemical change?
Apparatus:
Bunsen burner, 4 test tubes, a test tube rack and a test tube holder, small spatula, pipette, magnet, a birthday candle, NaCl (table salt), 0,1M AgNO
3 , 6M HCl, magnesium ribbon, iron filings, sulphur.
Note: AgNO
3 stains the skin. Be careful when working with it or use gloves.
Method:
Place a small amount of wax from a birthday candle into a test tube and heat it over the bunsen burner until it melts. Leave it to cool.
Add a small spatula of NaCl to 5 ml water in a test tube and shake. Then use the pipette to add 10 drops of AgNO
3 to the sodium chloride solution. NOTE: Please be careful AgNO
3 causes bad stains!!
Take a 5 cm piece of magnesium ribbon and tear it into 1 cm pieces. Place two of these pieces into a test tube and add a few drops of 6M HCl. NOTE: Be very careful when you handle this acid because it can cause major burns.
Take about 0,5 g iron filings and 0,5 g sulphur. Test each substance with a magnet. Mix the two samples in a test tube and run a magnet alongside the outside of the test tube.
Now heat the test tube that contains the iron and sulphur. What changes do you see? What happens now, if you run a magnet along the outside of the test tube?
In each of the above cases, record your observations.
Questions:
Decide whether each of the following changes are physical or chemical and give a reason for your answer in each case. Record your answers in the table below:
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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