In the periodic table, what is the property that decreases along the periodic and increases down the group?
- A. Atomic number
- B. Electron affinity
- C. Ionization potential
- D. Atomic radius
The electron configuration of two elements with similar chemical properties are represented by?
- A. 1s22s22p5 and 1s22s22p4
- B. 1s22s22p4 and 1s22s22p63s1
- C. 1s22s22p63s1 and 1s22s1
- D. 1s22s22p4 and 1s22s1
The temperature of a body decreases when drops of liquid placed on it evaporate because?
- A. the atmospheric vapour pressure has a cooling effect on the body
- B. a temperature gradient exists between the drops of liquid and the body causing the latter to vaporate
- C. the heat of vapourization is drawn from the body causing it to cool
- D. the random motion of the liquid molecules causes a cooling effect on the body
A mixture of 0.20 mole of Ar, 0.20 mole of N2 and 0.30 mole of He exerts a total pressure of 2.1 atm. The partial pressure of He in the mixture is?
- A. 0.90 atm
- B. 0.80 atm
- C. 0.70 atm
- D. 0.60 atm
An element, X, forms a volatile hydride XH3 with a vapour density of 17.0. The relative atomic mass of X is?
(H = 1)
- A. 34.0
- B. 31.0
- C. 20.0
- D. 14.0
2.85g of an oxide of copper gave 2.52g of copper on reduction and 1.90g of another oxide gave 1.52g of copper on reduction. The data above illustrates the law of?
- A. constant composition
- B. conservation of mass
- C. reciprocal proportions
- D. multiple proportions
35 cm3 of hydrogen was sparked with 12 cm3 of oxygen at 110°C and 760mm Hg to produce steam. What percentage of the total volume of gas left after the reaction is hydrogen?
- A. 11%
- B. 31%
- C. 35%
- D. 69%