Chemistry Form 1 Notes It does not burn or support combustion, except in extreme cases, and is not poisonous (it is the gas in fizzy cool drinks). Chemistry Questions and Answers Pdf for Class 12 The magnesium ribbon continues to burn in carbon dioxide. (c) The experiment was repeated with a piece of potassium of the same size. Each oxygen atom has six electrons in the outer shell. A negative ion is sometimes called an anion since it drifts to the anode during electrolysis. chloride Cl- because they are one electron short of a noble gas electron structure. There are three different crystal forms of silicon dioxide. Carbon dioxide is easily prepared by the action of dilute hydrochloric acids on metal carbonates (normally calcium carbonate or marble). Ions remaining in solution It therefore has a charge of 1-. The modern periodic table is very useful for giving a summary of the atomic structure of all the elements. Soda-acid fire extinguishers produce carbon dioxide to put out fires. The electrons revolve rapidly around the nucleus in fixed circular paths called energy levels or shells. When carbon dioxide is passed over red-hot carbon in the form of coke charcoal, the carbon dioxide loses one of its two atoms of oxygen. Filtration Two students made the insoluble salt, lead sulphate, and wrote these notes about the experiment. Each water molecule is hydrogen bonded to four others. In an electrical circuit, metals can conduct electricity because the mobile electrons can move through the structure carrying charge. We stirred the mixture and filtered it to In metals, as well as this effect, the 'hot' high kinetic energy electrons move around freely to transfer the particle kinetic energy more efficiently to 'cooler' atoms. The giant covalent structure of silicon dioxide Ions are charged particles e.g. One full shell i.e. Assessment 3 Non-metallic negative anions are attracted and may be oxidised to the free element. Very strong silicon-oxygen covalent bonds have to be broken throughout the structure before melting occurs. reject other particles for second mark The flow of electricity is due to the flow of the ions. 2. In the formation of the molecule, each nitrogen atom contributes three electrons and a triple bond is formed These impurities can be removed by pumping the liquid through the filter press and then passed through cooling pipes. (a) Use the information in this table to explain why these elements are placed in the same group. (b) Boiling point increases as the atomic number increases; The resources include teaching/learning class notes, Topical (topic by topic) Questions and Answers, Termly Examination Papers and Marking Schemes, Lesson Plans, Powerpoint Notes and Slides, Schemes of Work, KCSE KNEC Past Papers, Confidentials and … .61 9. Deduce the percentage abundance of the two isotopes in bromine. The symbol represents an atom of sodium whose atomic mass is 23 and atomic number is 11. This means that the atomic number and mass number both increase as we move down the group. Uses of Carbon Dioxide Atoms combine with each other in simple whole number ratios to form compound atoms called molecules. Electrolysis of many salt solutions such as sulphates, sulphuric acid etc. Properties of ionic compounds What type of bond is present in water molecules? Metallic character reduces while going from left to right in a period. Preparation of carbon monoxide The boiling points of ethanol and methoxymethane show the dramatic effect that the hydrogen bonding has on the stickiness of the ethanol molecules: ethanol (with hydrogen bonding) 78.5°C (b) Use the Periodic Table provided and the information above to suggest the likely properties of fluorine. • The atomic numbers are not consecutive. is applied across a piece of metal. Chemistry Form 3 Notes Pdf . sodium chloride Na+Cl-. Biology Notes Form 1 This can be got by heating limestone. When an alkali metal atom reacts, it loses an electron to form a singly positively charged ion e.g. . Electroplating It is also one of the stable forms of carbon. Beryllium is odd and is not studied at KCSE. 1. .65 1B. (a) B D A C E;; KCSE Revision Notes Form 1 - Form 4 All Subjects The total care of patients was provided to RRVE. Hydrogen bonding can occur between ethanol molecules, although not as effectively as in water. the weaker is the electrolyte. Helium's intermolecular attractions are even weaker - the molecules won't stick together to form a liquid until the temperature drops to (-269°C). continue to burn in carbon dioxide. This means that the sodium ions and the hydroxide ions remain in the solution - i.e. . As the number of protons in the nucleus increases going down Group 2, you might expect the atomic radius to decrease because the nuclear charge increases. A small piece of sodium is dropped into a large beaker of water. Carbon + nitric acid carbon dioxide + Nitrogen (IV) oxide + water They become positive ions because they have lost electrons but the number of protons in the nucleus has remained unchanged. • The attraction created by hydrogen bonds keeps water liquid over a wider range of temperature than is found for any other molecule its size. Also the chemical reactivity first decreases and then increases. Solutions of salts in water Inorganic and Applied Chemistry. The reaction between ammonia and hydrogen chloride Hence they can slide over one another. Carbon dioxide is neither combustible, not a supporter of combustion. form-4 23 esters. 3. The ratio of volumes is about 2:1 for hydrogen and oxygen respectively. After the covalent double bond is formed, each atom has 8 electrons around it as shown. Chemistry Questions and Answers Pdf Study the given table: Most of these atoms try to attain the configurations of either neon (2,8) or argon (2,8,8). The energy associated with moving charges is called current or electricity. Wood Charcoal is not a conductor of electricity. It is transparent to light and X-rays. 1. Interesting Chemistry Questions You can't do electrolysis with an ionic solid! Chemical decomposition takes place. Chlorine This is because of the relatively large amount of space that is "wasted" between the sheets. Basic rules for electroplating an object metal M are as follows: We are currently looking for a senior consultant in the analysis of Lotus Notes applications and their ecosystems. (ii) What is the name of the negative ion present in sodium chloride? Electrolysis of Lead Bromide. Nature 3. These materials carry an electric current via freely moving electrically charged particles, when a potential difference (voltage) is applied across them, and they include: • moves about; Describe how a covalent bond is formed between two chlorine atoms. Geography Notes Form 1 The ions that are removed from the solution, then, are the hydrogen ions and the chloride ions. Both these uses have now been banned by international law, in the developed world at least. Also check out our other helpful revision resources for O Level Chemistry (5070). Carbon + sulphuric acid carbon dioxide + sulphur dioxide +water, C(s) + 2H2SO4(conc) CO2(g) + SO2(g) + 2H2O(l), Carbon + nitric acid carbon dioxide + Nitrogen (IV) oxide + water, C(s) + 4HNO3 (conc) CO2(g) + 4NO2(g) + 2H2O(l). Allotropy is the existence of the same chemical in different physical forms. Carbon reacts with oxygen to form two oxides, carbon dioxide, CO2, and carbon monoxide CO. So what holds the sheets together? Hydroxide ions oxidised to oxygen gas molecules. Ammoniacal brine next enters the carbonating tower from the top. The electrolyte is the salt of the metal to be coated on the article. Chemical reactions occur so that atoms attain inert gas configuration by either losing valency electrons as in the case of metals, or gaining electrons as in the case of non metals. for softening hard water The problem these chemicals cause is that when they reach the high atmosphere the molecules break apart to release chlorine atoms. Halide ions undergo a series of unique reactions that allow an unknown solid or aqueous sample to be tested for the presence of chloride, bromide or iodide ions. Baking powder contains starch, sodium hydrogen carbonate and an acid forming ingredient, such as tartaric acid of calcium hydrogen phosphate [Ca(H2PO4)2] or alum [Na2SO4.Al2(SO4)3.24 H2O]. In 1829 Dobereiner suggested that some elements could be put into groups of three because they had similar chemical properties. Chemistry Multiple Choice Questions and Answers Pdf Biology Questions and Answers Form Two Wood Charcoal At the same time the hot carbon also gets converted to carbon monoxide. [Deduct 1 mark for incorrect inner electrons] C(s) + 2H2SO4(conc) CO2(g) + SO2(g) + 2H2O(l) From calcium going down the group, they have to be stored under oil, or they react with oxygen in the air. When ionically bonded substances are melted or dissolved in water, the ions are free to move about. The melting and boiling point increases because the atoms become heavier (bigger) and require more energy to melt or boil. 3) Covalent compounds generally have low melting and boiling points. (a) (i) 4 electrons/same number of electrons in outer shell; • carbon and silicon both in group 4/same group/same number These bonds are hard to break, therefore ionic substances have very high melting and boiling points. By the decay of organic matter, like the dead bodies of animals and plants. Chemistry Form 1 Notes Pdf It has fewer shells so less screening of the outer electrons from the nucleus, stronger attraction to the nucleus. (b) one electron on each hydrogen atom; Calcination (i) Name a noble gas used in one of these ways. If need be, the gas should be prepared in a fume chamber. The elements of the same period have different valencies. It does not react with any substance at ordinary temperatures. Bromine and iodine are both used in 'halogen' car headlamps. Diamond is the purest form of natural carbon. LITERATURE IN ENGLISH FORM FOUR PAST PAPERS. The sodium ions and chloride ions are held together by the strong electrostatic attractions between the positive and negative charges. The ions that are successfully released (or discharged) at the electrodes depend on three factors: Second ionization energy is higher than the first ionization for each element. Elements in a given group in the periodic table share many similar chemical and physical properties. Magnesium will react with gaseous water (steam) to form magnesium oxide and hydrogen. hydrochloric acid ,chloride ion oxidised to chlorine gas molecules. In other words, ice is less dense than liquid water and will float on the surface of the liquid. The forces of attraction which hold an individual molecule together (for example, the covalent bonds) are known as intramolecular attractions. It is made up of sub-atomic particles like electrons, protons and neutrons. Oxygen collects at the anode. Columns in the periodic table are called groups. Essential Electromagnetism: Solutions. It is used for making electrotypes for printing. Introduction 1. Due to the presence of a free valence electron, it is a good conductor of electricity. . The chlorine has gained an electron, so it now has one more electron than proton. It is the purest form of the amorphous variety of carbon. • Alkali metals burn very exothermically and vigorously when heated in chlorine to form colourless crystalline ionic salts eg NaCl or Na+Cl-. After the silos are packed with the food grains, carbon dioxide is pumped into the silos from the top. The chlorine atom gains the electron and it becomes negatively charged ion. 1. Chemistry Form One Book Pdf Magnesium is very reactive with dilute hydrochloric acid forming the colourless soluble salt calcium chloride and hydrogen gas. Usually a relatively large amount of energy is needed to melt or boil metals. Chemical Properties of Graphite form-4 24 soap. . Chemistry Form 4 Exercise This enhanced attraction is called surface tension. Successive ionisation energies always increase e.g. It has been reported that the hydrogen element has atoms with mass number 2 and 3 also i.e. (c) (i) covalent (bonding); 1. Carbon monoxide is produced whenever organic matter is burnt in a limited quantity of oxygen. a) Carbon dioxide is used in photosynthesis by green plants to produce carbohydrates. (a) (i) electron(s); Particles in solid are not free to move around. Water is a poor conductor of electricity. Industrial preparation The article to be electroplated is made cathode since metallic ions are positive and thus get deposited on the cathode. It is used in the preparation of artificial diamonds. . c. Typical metals also have a silvery surface but remember this may be easily tarnished by corrosive oxidation in air and water. Klb Chemistry Book 2 Notes Pdf Carbon dioxide is slightly acidic. Ice and Hydrogen Bonding Reducing action of carbon Their melting and boiling points are very low because when these four substances melt or boil, it is the van der Waal’s forces between the molecules which are broken. (b) (i) chlorine; 1.By dehydrating oxalic acid with hot concentrated sulphuric acid. HISTORY FORM THREE TOPIC 1: ESTABLISHMENT OF COLONIALISM. Home (Honors, AP & College Chemistry Notes) *Back out of Pdf files to get back to the website! 4. (ii) What safety precaution should be taken when measuring out the acid? The bonding in graphite This tower is partitioned using horizontal plates that have a central hole and covered with a perforated plate. For example, common table salt, sodium chloride, is an ionic substance that contains alternating sodium and chlorine ions. Mg + Br2 --> MgBr2, Summary of the Reactivity Trend of Alkali Earth Metals, As the atomic radius increases and the electron is further from the nucleus it is less attracted to the nucleus (electron is said to be 'shielded'). 2. Indoor fireplaces can be a serious hazard if ventilation is poor. Conductors As you go down a group the ionisation energy decreases. (b) The table gives the boiling points of the noble gases. Calcium burns quite fast with a brick red flame when strongly heated in air/oxygen to form the white powder calcium oxide. The anode is made of pure metal, which is to be coated on the article. (ii) In which group of the periodic table is potassium found? These are supposed to have been formed by the crystallization of carbon under extreme pressure and temperature in the interior of the earth. Electrolysis of copper 11 sulphate solution using copper electrodes. ii) Colored quartz is used for manufacturing gems. [Accept appropriate relevant statements for 1 mark each] Repair of finer machine parts. The concentration of the ions The last element in the period is neon (Ne, Z=10). Effectively, this experiment is the electrolysis of water.`, Example: Electrolysis of copper II sulphate solution.
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