Which one of the following is not an element

Question: Which one of the following is not an element

(a) Diamond

(b) Graphite

(c) Silica

(d) Ozone

Correct Answer: (c) Silica

More Question

1. A sample of pure carbon dioxide, irrespective of its source contains 27.27% carbon and 72.73% oxygen. The data support [AIIMS 1992]
2. After a chemical reaction, the total mass of reactants and products [MP PMT 1989]
3. An element forms two oxides containing respectively 53.33 and 36.36 percent of oxygen. These figures illustrate the law of
4. Which of the following is the best example of law of conservation of mass [NCERT 1975]
5. n g of substance X reacts with m g of substance Y to form p g of substance R and q g of substance S. This reaction can be represented as, X + Y = R + S. The relation which can be established in the amounts of the reactants and the products will be
6. A sample of calcium carbonate Ca(CO)₃ has the following percentage composition : Ca = 40%; C = 12%; O = 48% If the law of constant proportions is true, then the weight of calcium in 4 g of a sample of calcium carbonate obtained from another source will be
7. Carbon and oxygen combine to form two oxides, carbon monoxide and carbon dioxide in which the ratio of the weights of carbon and oxygen is respectively 12 : 16 and 12 : 32. These figures illustrate the
8. Two elements X and Y have atomic weights of 14 and 16. They form a series of compounds A, B, C, D and E in which the same amount of element X, Y is present in the ratio 1 : 2 : 3 : 4 : 5. If the compound A has 28 parts by weight of X and 16 parts by weight of Y, then the compound of C will have 28 parts weight of X and [NCERT 1971]
9. Different propartions of oxygen in the various oxides of nitrogen prove the [MP PMT 1985]
10. Avogadro number is
11. Chemical equation is balanced according to the law of [AMU 1984]
12. Two samples of lead oxide were separately reduced to metallic lead by heating in a current of hydrogen. The weight of lead from one oxide was half the weight of lead obtained from the other oxide. The data illustrates [AMU 1983]
13. The percentage of copper and oxygen in samples of CuO obtained by different methods were found to be the same. This illustrates the law of [AMU 1982, 92]
14. Among the following pairs of compounds, the one that illustrates the law of multiple proportions is
15. 1.0 g of an oxide of A contained 0.5 g of A. 4.0 g of another oxide of A contained 1.6 g of A. The data indicate the law of
16. Which of the following pairs of substances illustrate the law of multiple proportions [CPMT 1972, 78]
17. A sample was weighted using two different balances. The result’s were (i) 3.929 g (ii) 4.0 g. How would the weight of the sample be reported
18. The number of significant figures in 60.0001 is [Pb. CET 2000]
19. Given P = 0.0030m, Q = 2.40m, R = 3000m, Significant figures in P, Q and R are respectively [Pb. CET 2002]
20. The number of significant figures in 6.0023 are [Pb.CET 2001]
21. The significant figures in 3400 are [BHU 2004]
22. The prefix zepto stands for [DPMT 2004]
23. The number of significant figures in 6.02 x 10²³ is
24. 81.4 g sample of ethyl alcohol contains 0.002 g of water. The amount of pure ethyl alcohol to the proper number of significant figures is
25. In the final answer of the expression [(29.2-20.2)(1.79x10⁵)]/1.37 . The number of significant figures is [CBSE PMT 1994]
26. A mixture of methyl alcohol and acetone can be separated by
27. A mixture of ZnCl₂ and PbCl₂ can be separated by [AFMC 1989]
28. Which one of the following is not an element
29. In known elements, the maximum number is of [CPMT 1985]
30. Which of the following contains only one element
31. The compound which is added to table salt for maintaining proper health is
32. Which of the following elements of matter would best convey that there is life on earth
33. Difference in density is the basis of [Kerala MEE 2002]
34. Which of the following halogen can be purified by sublimation [Manipal PMT 2001]
35. Significant figures in 0.00051 are
36. Given the numbers : 161cm, 0.161cm, 0.0161 cm. The number of significant figures for the three numbers are [CBSE PMT 1998]
37. The prefix 10^18 is [Kerala MEE 2002]
38. Dimensions of pressure are same as that of [CBSE PMT 1995]
39. One atmosphere is equal to
40. A picometre is written as
41. One fermi is [Haryana CEET 1994; DPMT 2004]