When heat is absorbed during a chemical reaction, the reaction is said to be
thermodynamic
exothermic
isothermal
endothermic
thermostatic
Correct answer is D
No explanation has been provided for this answer.
nitrogen and carbondioxide
the rare gases
nitrogen and oxygen
nitrogen and the rare gases
nitrogen, carbondioxide and the rare gases
Correct answer is D
- Alkaline solutions of pyrogallol absorb oxygen efficiently.
- Quicklime have a strong chemical affinity to absorb water.
- At room temperature, Calcium oxide (CaO) will spontaneously absorb carbon dioxide from the atmosphere.
The oxidation state of chlorine in potassium chlorate is?
+1
+2
+3
+5
+7
Correct answer is D
- potassium chlorate --> KClO\(_3\)
valencies of K = +1, O = -2.
: (+1) + Cl + ( -2 X 3 atoms ) = 0
Cl + 1 - 6 = 0
Cl = 5
∴ The oxidation state of chlorine in potassium chlorate is +5
An element X forms the following compounds with chlorine; XCl4, XCl3, XCl2. This illustrates the
law of multiple proportions
law of chemical proportions
law of simple proportions
law of conservation of mass
law of definite proportions
Correct answer is A
this question expresses the law of multiple proportions which states that if two elements A and B combine together to form more than one compound, the various masses of element B which combines with a fixed mass of B are in simple whole number ratios. e.g
Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,
P will form an electrovalent bond with R
Q will form a covalent bond with S
R will form an electrovalent bond with S
Q will form an electrovalent bond with S
Q will form a covalent bond with R
Correct answer is D
P [6] = 2, 4
Q [11] = 2, 8, 1
R [15] = 2, 8, 5
S [17] = 2, 8, 7
Given the above is the electronic arrangement of PQRS elements, Q will form an electrovalent bond with S
Further explanation was provided by our student by name (Odebiyi Dare D-cent) via our facebook page. Thus he says:
without argument, D is the answer cos electrovalent involves the transfer of electron. Already, Q is 11 with elect configuration of 2,8,1, i.e having 1 valency electron which is ready to be loss by that atom of element Q, also, S is 17, with electronic configuration, with 2,8,7. There the 7valence electron of S attracts that nly 1 electron to attain a stable octet structure.