Nuclide XNR is an unstable isotope which decays in two stages into nuclide Z as shown:What are the values of P and Q? Answer: 3) B When an atom decays…

2.74g of 1-bromobutane is reacted with excess aqueous sodium hydroxide to produce 1.11g of butan-1-ol according to the equation below.C4H9Br + NaHO → C4 H9OH + NaBrWhat is the percentage…

Which of the following could result in a homeostatic response?1 A rise in an internal condition.2 A reduction in an internal condition.3 A rise in an external condition.4 A reduction…

At the front of a long column of soldiers is a man regularly hitting a drum 50 times a minute. The soldiers are told to place their left foot down…

An impurity in petroleum is dimethylsulphide, CH 3SCH3. When dimethylsulphide is burnt in an excess of air, which one of the following balanced equations represents the reaction that takes place?…

The graph below shows how one factor in the internal environment in a person changes, and is returned to a normal level. If someone has a condition which makes their…

I have two six-sided dice, each with faces numbered from 1 to 6. One of the dice is fair, but the other is not – it will land on numbers…

A ray of orange light travelling through air has a speed of 3.0 x 10 8 m/s and a wavelength of600nm. (1nm = 10 -9m)What could be the speed, frequency…

An ore of lead contains 70% of PbS. Calculate the mass of lead that can be extracted from 478kg of the ore.[Ar : Pb = 207; S = 32] Answer:…

Using the table, select the correct answer from the table.Cell Quantity of nuclear DNAP 1Q 2R 0 Answer: 21) D All body cells such as red blood cells and skin…