A Level H2 Chemistry Practical
Are you familiar with whats tested in A Level H2 Chemistry Practical or H2 Chemistry Paper 4?
For students taking H2 Chemistry, Chemistry practical or paper 4 is one of the papers they need to take. This practical exam accounts for 55 marks or 20% of the total chemistry score.
There are usually 4 questions in this paper, and these questions are typically :
Other Sources Of Hydrogen
Hydrogen gas can be prepared by reacting a dilute strong acid like hydrochloric acids with an active metal. The metal becomes oxides, while the H+ is reduced to hydrogen gas. This method is only practical for producing small amounts of hydrogen in the lab, but is much too costly for industrial production:
The purest form of H2 can come from electrolysis of H2O, the most common hydrogen compound on this plant. This method is also not commercially viable because it requires a significant amount of energy ):
\ is the most abundant form of hydrogen on the planet, so it seems logical to try to extract hydrogen from water without electrolysis of water. To do so, we must reduce the hydrogen with +1 oxidation state to hydrogen with 0 oxidation state . Three commonly used reducing agents are carbon , carbon monoxide, and methane. These react with water vapor form H2:
Reforming of Methane:
These three methods are most industrially feasible methods of producing H2.
Chemistry Is The Central Science
Most schools do not allow students to take Physics and Biology together. Instead, Chemistry is needed if you desire to take 2 sciences in JC. This is similar to the situation with the O-Level Combined Science combinations. This goes to show how important Chemistry is as a foundation for Science. H2 Chemistry is a rule-based application subject which will better assimilate you to the world of professionals who apply consistent sets of universally-agreed rules/principles.
You probably would have heard from seniors or relatives who have experienced JC saying H2 CHEMISTRY IS A KILLER!. Yes, it is a killer because it is not just content-heavy, but it is also about applications. Many O-Level graduates who simply got through their O-Level examinations by memorising and regurgitating content during exam would be disappointed that this would not work for H2 Chemistry. The application portion of H2 Chemistry will be a pain at first but it prepares us to be logical and methodical thinkers. In reality, most professionals such as Doctors, Dentists, Lawyers, Accountants and Engineers utilised consistent sets of universally-agreed rules/principles in their area of specialisations and this is strongly aligned with the skills you would acquire from H2 Chemistry.
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H3 Scheme Of Assessment
The A Level H3 Chemistry takes extra effort to pass, let alone score a distinction. Students who have passed the H2 stage and wish to understand better chemistry should go for it. The duration for H3, is a year, that is, at Junior College in the second year. The syllabus is also an extension of the chemistry of H2.
H3 chemistry, however, offers you a rewarding and satisfying experience with the subject. If you achieve excellent results, it adds value to your resume. Besides, it provides you with more chemistry knowledge that applies to professions related to the course.
Compared to H2, the H3 paper is a special-structured exam. You have only 2 hours and 30 minutes to sit for the H3 exam with 100 marks. The paper consists of two sections, A and B with a maximum of 60 marks in section A, while section B has 40. You also have a variable number of free-response compulsory questions in section A. There are 1 or 2 stimulus-based questions as well.
There are three free-response questions for Section B. Students will pick two exam questions containing 20 marks each. The paper tests, with understanding, your knowledge. Furthermore, H3 chemistry tests the ability to handle, apply and evaluate information.
Organic Chemistry What Is Reflux
January 17, 2015 By Sean Chua
We always see this reaction condition called Reflux when we study Organic Chemistry and their reactions.
I realised alot of students do not understand the true meaning of a reflux. This includes some of my JC2 and IB students who recently join our A-Level H2 Chemistry Tuition Classes.
So what really is Reflux?
Many organic chemical reactions take very long to complete, and in order to speed up these reactions, heat is applied. However, organic compounds are usually simple molecular structures with low boiling points. As such, most organic chemicals are quite volatile, and if heated they will evaporate and be lost. The solution to this problem is to heat the reaction mixture under reflux.
Diagram below shows the basic set-up of Refluxing:
Reflux involves heating the chemical reaction for a specific amount of time, while continually cooling the vapour produced back into liquid form, using a condenser. The vapours produced above the reaction continually undergo condensation, returning to the flask as a condensate.
The reactants for reflux experiments can be solid and liquid, or both liquids.
The condenser is always completely filled with water to ensure efficient cooling.
The vapours, which are given off from the liquid reaction mixture, change from gas phase back to liquid phase due to heat loss. This then causes the liquid mixture to fall back into the round bottom flask.
How Is Hydrogen Produced
Hydrogen can be prepared through several methods. Two such methods are listed below.
- Reacting natural gas with steam of very high temperature in order to obtain a mixture of hydrogen gas, carbon monoxide, and carbon dioxide.
- Passing an electric current through water to split it into hydrogen and oxygen molecules
Which Is The Best H2 Or H3 Chemistry
If you decided to take on H3 Chemistry and would like extra help to ensure you get the best experience and exam results, Julian Chemistry has comprehensive A Level Tuition classes that include JC2 H3 Pharm Chemistry classes. For more information on why you should choose H2 Chemistry, click on this link!
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How To Score A For A
Why does my child struggle to pass his A-Level Higher 2 Chemistry examination when he has scored A1 for his O-Level Chemistry or IP Chemistry?
In fact, Mr Sean Chua has to answer this question so frequently. We speak to him to find out what students should do to score in their A-Level H2 Chemistry.
Physical Chemistry In A Level H2 Chemistry Practical
There is usually a practical question on physical chemistry typically reaction kinetics or chemical energetics, although some other topics like equilibrium do come out.
For reaction kinetics, the experiments conducted revolve around tests to determine order of reaction with respect to the reactants.
For chemical energetics, the experiment are usually quite straight forward adding the reactants together and measuring the temperature change. Once the data is obtained from the experiment, its calculation time! Usually the questions will involve finding the heat change , Q using the formula Q = mcT. From there, students can find the enthalpy change by taking Q/ n where n is the number of moles.
Sometimes, students are expected to use Hess Law to find another enthalpy change of another reaction, so make sure you are familiar with apply Hess Law. This can also come out as a planning question.
Within the Scheme of Assessment, Paper 4 is weighted to 20% of the Higher 2 assessment. It is thereforerecommended that the schemes of work include learning opportunities that apportion a commensurateamount of time for the development and acquisition of practical skills. The guidance for practical work, whichis published separately, will provide examples of appropriate practical activities.
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Transitioning From Combined Science To Jc Chemistry
If you are taking Chemistry for O Levels, then you will surely be aware of the differences between combined science and pure chemistry. A question that then arises is whether you should pursue H2 Chemistry or even H1 Chemistry, if you have only previously taken chemistry as part of combined science.
Factually, pure chemistry students do have a slight head start, having covered the basics of the following topics:
Macroscopic Understanding In The Jc Chemistry Syllabus
With a wealth of experience coupled with updated compendium on how to tackle the JC Chemistry syllabus, we are well armed to help students connect the dots between different chemical concepts from Redox to acids and energetics. This is an essential skill to help students cope with the rigor of the A Level Chemistry program.
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Key Milestones In The History Of Hydrogen
1671: Anglo-Irish Scientist Robert Boyle produced hydrogen gas for the first time while experimenting with iron and acids.
1766: British physicist Henry Cavendish first identified hydrogen as a distinct element. During his experiment, he evolved hydrogen gas by reacting zinc metal with hydrochloric acid.
1783: French physicist, Jacques Alexander Cesar Charles, launched the first hydrogen balloon flight.
1783: French chemist Antoine Lavoisier named the gas hydrogène which is derived from the Greek word hydro and genes, meaning water and born of.
1838: German-Swiss chemist Christian Friedrich Schönbein invented the fuel cell, which led to power generation out of hydrogen and oxygen.
1842: British Physicist Sir William Grove developed the first fuel cell which produced electrical energy by combining hydrogen and oxygen. He is called Father of the Fuel Cell.
1898: Scottish scientist Sir James Dewar turned hydrogen to a liquid form by cooling it down to -252.87°C.
1921: German physical chemist Karl Friedrich Bonhoeffer and Austrian chemist Paul Harteck works showed the two types of molecules: ortho-hydrogen and para-hydrogen.
Uses Of Hydrogen Gas H2
- Hydrogen gas is being explored for use in combustion engines and fuel cell electric vehicles.
- The flame of oxygen and hydrogen can generate a temperature of 2800oC. This oxy-hydrogen flame is used for cutting and welding metals.
- Used for the hydrogenation of vegetable oils that is converting edible vegetable oils into vanaspati ghee.
- Equal volume of hydrogen and helium gas is used for filling weather observation balloons.
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Imparting Core Skills Such As Deductive Skills
H2 chemistry teaches students how to develop hypotheses, a skill that is useful for research. It also strengthens students critical abilities and teaches them appropriate ways of constructing evidential and logical explanations. At Seb Academy, the realistic aspect of H2 chemistry also helps students hone their planning skills by applying what they have learned to perform experiments. Deductive skills are the most precious qualities conferred to the H2 Chemistry student, and this is not only targeted towards academics and scoring distinctions. It allows a student to appreciate deeply, Chemistry and develop a keen and intuitive guide to hypothetical thinking and making logical deductions as an individual. This is a valuable quality which would aid you in your career development as a person with quick deductive skills, sound logical decisions while developing strong hypothesis and testing them. And this is a core belief for Seb Academy pedagogy for our JC Chemistry tuition program.
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Nuclear Charge And Screening Effect
Because moving across a period increases both the number of protons and electrons, nuclear charge and screening effect will increase1.
However, you will earn that because the nuclear charge increases to a larger extent compared to the screening effect, the increase in nuclear charge outweighs that of screening effect, and the net nuclear charge increases.
Therefore, the size of an atom decreases across a period.
Yet down a group we have it differently.
This time, the size of an atom increases down a group because the screening effect due to an increase in the number of electrons or electronic shells greatly outweighs that of nuclear charge due to an increase in protons.
Titration Question In A Level H2 Chemistry Practical
In titration, students are expected to find the concentration of a solution, but titrating it against a known concentration of another solution. In A Level titration questions, it is also common for students to be asked to prepare standard solution using a graduated flask.
Titration reactions are often acid- base or redox. Acid- base titrations would require an indicator . Redox reactions are sometimes self- indicating .
After completing the titration, students are often asked to do calculation. To do so, students must be familiar with the topic on mole concept and stoichiometry.
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What Is The Chemical Equation For Water
H2O2H2 + O2 2H2O Chemical equations give the following information about chemical reactions. Chemical equations show the formulas for the substances that take part in the reaction. The formulas on the left side of the arrow represent the reactants, the substances that change in the reaction.
What is the chemical equation for H2O?, For example, it is known that two molecules of hydrogen gas, H2, react with one molecule of oxygen gas, O2, to form two molecules of water, H2O. This reaction may be represented by the chemical equation 2H2+O22H2O.
Furthermore, What type of reaction is H2 O2 H2O?, Type of Chemical Reaction: For this reaction we have a Combination reaction. Balancing Strategies: For this reaction it is helpful to start by changing the coefficient in front of H2O and so that you have an even number of oxygen atoms.
Finally, What type of reaction is H2 O2 h2o?, Type of Chemical Reaction: For this reaction we have a Combination reaction. Balancing Strategies: For this reaction it is helpful to start by changing the coefficient in front of H2O and so that you have an even number of oxygen atoms.
A Streamlined Programme To A Levels Examination Preparation At Seb Academy
While O Level Chemistry focuses on factual content, A Level Chemistry concentrates more on interpreting and applying scientific concepts and principles. Seb Academys pedagogy is in imparting advanced techniques to students to recognize the need to build skills and long-term values in an increasingly technical environment rather than relying on large volumes of factual material that may have only short-term relevance. Rote learning can only help so much at the A levels. If youre looking for a career path in the sciences industry, the A Level H2 Chemistry will help put you one step closer to achieving that goal.
Our A Level Chemistry Tuition Program is headed by Mr Sam Lee.
Please click here to view more on Mr Lees teaching experience.
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Are You Having Too High Expectations For Your Child
We understand your concern. Who wouldnt want your child to score outstanding results and gain admission to a university course of their choice? Most parents expect your child to continue to perform at an acceptable level in the Junior College. But many students gave their parents a shock with their first term results which are in a sea of red.
In my opinion, parents must understand the transition your child is going through before setting their expectation. It is also important that you have open communication with your child to find out why they are not performing.
What could be the major problem students face when they transit from O-Level Chemistry or IP Chemistry to H2 Chemistry?
Years Of Experience In Jc Chemistry
Struggling to connect the dots between Chemistry concepts? Seb Academy JC Chemistry Tuition is different from the other chemistry tuition program as we have lectured through many years, helping many students to achieve their As through the years. As such, we know the syllabus so well to help students chart their progress for the A level.
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Is Hydrogen The Most Abundant Element In The World
No. In the universe , hydrogen is the most abundant element and accounts for 75% of the share, followed by helium which accounts for 24%. Together these two elements account for 99% of the universe. However, please do not confuse these figures with our planet earth.
Indeed hydrogen exists in abundance as a compound such as water, part of living bodies, carbon compounds, and atmosphere. However, it is not the most abundant element in the world. The chemical composition of our earth is slightly different from that of the universe.
The earth crusts chemical composition consists of oxygen, the leading element with 46.10% of weight, followed by silicon, aluminium, iron, calcium, sodium, potassium, and magnesium. The crust is only the outer body of the earth which is between 5km to 10km. However, very little is known about the core and mantle, though the amount of hydrogen is considered negligible. The earth atmosphere is almost 99% composed of nitrogen and oxygen, so very little hydrogen can be found in the form of gas or vapour. The only part where we can find abundant hydrogen is water, though it still paired with oxygen as a compound. Water covers 71% of the earths surface, whereas the oceans account for about 96.5% of all earths water. In ocean water, hydrogen accounts for around 10.8% of the total mass.
|Source: H2 Bulletin, Jefferson Lab, Literature Review
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