Chemistry · Karatasi 2 · 2012
48 maswali 🇹🇿 NECTA ✓ MSChemistry · Karatasi 2 · 2012
48 maswali
Mtihani wa saa 3 wa muda · husahihishwa kiotomatiki · huhesabiwa kwenye nafasiMazoezi ya saa 3 · husahihishwa moja kwa moja · huhesabika kwenye nafasiMazoezi ya saa 3 · husahihishwa moja kwa moja · huhesabika kwenye nafasi
Lipa na anza mtihani →Maswali (48)
Sehemu B
Match each item in List A with a correct response in List B by writing its letter below the number of the corresponding item in the table provided.
- A method used to separate mixtures of two or more liquids that form homogeneous solution by means of fractional column. (1 alama)
- A method used to separate mixtures of two or more liquids that form homogeneous solution by means of fractional column. (1 alama)
- A substance that absorbs moisture from the atmosphere and dissolves in it. (1 alama)
- Elements with stable structure. (1 alama)
- Elements with stable structure. (1 alama)
- Molecular mass of calcium carbonate. (1 alama)
- Molecular mass of calcium carbonate. (1 alama)
- Poisonous gases prepared in it. (1 alama)
- Poisonous gases prepared in it. (1 alama)
- Produces a "pop" sound. (1 alama)
- Quiet and unsteady flame. (1 alama)
- Smokeless solid fuel. (1 alama)
- Smokeless solid fuel. (1 alama)
- Source of energy derived from animal waste. (1 alama)
- Source of energy derived from animal waste. (1 alama)
- Used to prevent direct heat to reach the apparatus. (1 alama)
- Used to prevent direct heat to reach the apparatus. (1 alama)
Boresha ili kuona majibu ya mfano.
The following are possible causes of accidents which can occur in the Chemistry laboratory. State how you can avoid them. (i) Poisonous chemicals left in an unlocked cupboard (ii) A student picking up a bottle containing concentrated H₂SO₄ acid by the neck (iii) Concentrated acids stored in the uppermost shelf of cupboard
- List down four careers that are a result of studying Chemistry. (4 alama)
- State how you can avoid concentrated acids stored in the uppermost shelf of cupboard. (1 alama)
Boresha ili kuona majibu ya mfano.
Sehemu C
Mariam was preparing food for her family using hot oil in a frying pan. Accidentally the pan tripped over and a huge fire spread over her kitchen floor. (i) Mention two extinguishers which would be appropriate for putting out the fire. (ii) Which fire extinguisher would be dangerous to use when trying to put out the fire in (a) above? Give reason. (b) Mention three conditions for a fire to start. (c) (i) What is combustion? (ii) Give three areas where combustion is applied.
- Which fire extinguisher would be dangerous to use when trying to put out the fire in (a) above? Give reason. (3 alama)
- Mention three conditions for a fire to start. (3 alama)
- Give three areas where combustion is applied. (3 alama)
Boresha ili kuona majibu ya mfano.
In an experiment, two iron nails A and B were used whereby painting was applied on nail A. The two nails were placed in a moist environment and after one month the weight of each nail was determined. Which of the two nails would be heavier? Give reason. (b) State the method which will be used to protect each of the following from rusting: (i) Covering iron sheets with a layer of most reactive metals (ii) Bicycle chain (c) Find the oxidation number of the underlined elements in the following: (i) MnO₄⁻ (ii) K₂Cr₂O₇
- In an experiment, two iron nails A and B were used whereby painting was applied on nail A. The two nails were placed in a moist environment and after one month the weight of each nail was determined. Which of the two nails would be heavier? Give reason. (3 alama)
- Bicycle chain (1 alama)
- K₂Cr₂O₇ (3 alama)
Boresha ili kuona majibu ya mfano.
Write the chemical symbol for each of the following elements: (i) Silver (ii) Lead (iii) Manganese
- Name the type of bonds that will be formed in the combination between S and T. (0 alama)
- How many neutrons are present in element Q? (1 alama)
- Write the chemical symbol for Manganese. (0 alama)
Boresha ili kuona majibu ya mfano.
(i) Which is the most abundant element on the earth’s outer crust? (ii) The term used for acidic chemicals which can burn your skin is (iii) Give the name of a flame which forms soot
- Give two properties of the bond you have mentioned in (a)(ii) above. (0 alama)
- Give the name of a flame which forms soot (1 alama)
- Define Funnel Separation. (1 alama)
Boresha ili kuona majibu ya mfano.
(i) State the modern periodic law (ii) Give the special name for each of the following groups of elements in the periodic table: Group I Group VII (iii) Why is the atomic number a better way of identifying an element than the mass number?
- Give the name of a bond which can be formed between two oxygen atoms. (1 alama)
- Explain why a magnesium oxide has no overall charge. (1 alama)
- Why is the atomic number a better way of identifying an element than the mass number? (0 alama)
Boresha ili kuona majibu ya mfano.
List four uses of hydrogen in our daily life.
- Mention four physical properties of water. (4 alama)
- List four uses of hydrogen in our daily life. (4 alama)
- What will happen when hydrogen gas reacts with oxygen gas? (1 alama)
Boresha ili kuona majibu ya mfano.
Sehemu D
The following is a set of apparatuses which are used for heating:
Mention three categories of fuel and give two examples in each category.
- Give two points of advice to the society on how to use less charcoal and firewood efficiently. (2 alama)
- What is fuel? (1 alama)
- Explain why petroleum and coal are non-renewable resources of energy. (2 alama)
- Mention three categories of fuel and give two examples in each category. (6 alama)
Boresha ili kuona majibu ya mfano.