Chemistry Past Questions And Answers
Potassium and sodium show similar chemical properties because they?
- A. belong to the same group in the Periodic table
- B. have equal number of electrons in their outermost shells.
- C. both exist in the + 1 oxidation state in their compound
- D. belong to the same period in the Periodic Table
Which of the following statements is not a postulate of the kinetic theory of gases?
- A. Molecules move with the same speed
- B. intermolecular forces are negligible
- C. Molecules are in a state of constant random motion
- D. collision between molecules is elastic
The salt that reacts with dilute hydrochloric acid to produce a pungent smelling gas which decolourizes acidified purple potassium tetraoxomanganate (VII) solution is
- A) Na2SO4
- B) Na2SO3
- C) Na2S
- D) Na2CO3
A compound that will NOT produce oxygen on heating is?
- A. potasium dioxonitrate (III)
- B. lead (IV) oxide
- C. potassium trioxochlorate (V)
- D. potassium trioxonitrate (V)
The concentration of a solution obtained by dissolving 0.53g of pure anhydrous Na\(_2\)CO\(_3\) in water to make 250 cm\(^3\) of solution is
- A)2.0 \(\times\) 10-5 moldm\(^{-3}\)
- B)2.1 g dm\(^{-3}\)
- C)2.0 \(\times\) 10-2 moldm\(^{-3}\)
- D)5.0 \(\times\) 10-3 moldm\(^{-3}\)
The effect of the presence of impurities such as carbon and sulphur on iron is that they
- A) give it high tensile strenght
- B) make it malleable and ductile
- C) increase its melting point
- D) lower its melting point
The shapes of CO2, H2O and CH 4 respectively are
- A. bent, linear and tetrahedral
- B. bent, tetrahedral and linear
- C. linear, bent and tetrahedral
- D. tetrahedral, linear and bent
32g of anhydrous copper(ii)tetraoxosulphate(vi) dissolved in 1dm^3 of water generated 13.0kj of heat. The heat solution is?
- A. 26.0kj/mol
- B. 65.0kj/mol
- C. 130.0kj/mol
- D. 260.0kj/mol
Cellulose and starch can be classified as one of the following
- A) hydrocarbons
- B) sugars
- C) carbohydrates
- D) alkaloids
Which of the following mixture of gases is likely to burn in flame
- A. neon and hydrogen
- B. nitrogen and helium
- C. helium and neon
- D. neon and nitrogen