Has 9 protons and 9 electrons in per atom.........
The scientist that performed the cathode ray experiment leading to the discovery of electrons is J.J. Thomson.
<h3>What is a cathode ray?</h3>
A cathode ray is a tube that contains negatively charged electrode( that is the cathode) which emits electrons when heated at a low pressure.
The cathode ray was used by the scientist, J.J. Thomson to find the ratio of charge to mass (e/m) of the electrons.
Therefore, the scientist that performed the cathode ray experiment leading to the discovery of electrons is J.J. Thomson.
Learn more about electrons here:
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Place the mixture in hot water and stir well.
<span>The KNO3 is very soluble in hot water. </span>
<span>Use a fine filter paper and filter off the sand. </span>
<span>The sand will be separated from the KNO3 solution. </span>
<span>The water can now be evaporated from the solution by further, gentle heating leaving the solid in the container.</span>
Answer:
ΔH =
Explanation:
In a calorimeter, when there is a complete combustion within the calorimeter, the heat given off in the combustion is used to raise the thermal energy of the water and the calorimeter.
The heat transfer is represented by
= 
where
= the internal heat gained by the whole calorimeter mass system, which is the water, as well as the calorimeter itself.
= the heat of combustion
Also, we know that the total heat change of the any system is
ΔH = ΔQ + ΔW
where
ΔH = the total heat absorbed by the system
ΔQ = the internal heat absorbed by the system which in this case is 
ΔW = work done on the system due to a change in volume. Since the volume of the calorimeter system does not change, then ΔW = 0
substituting into the heat change equation
ΔH =
+ 0
==> ΔH =
A measured value is expressed as a number along with a corresponding unit. The unit represents the dimension of the measured value.
For example:
- Length of an object can be expressed as, value + dimension. for example 10 m where 'm' is the dimension of length; meters
- Volume can be expressed as, value + dimension, for example, 10 L where L is the dimension of volume; Liters.
Ans C) Dimension