Answer : The correct answer is Option D.
Explanation:
Ores are defined as natural occurring substance from which metals and another mineral are extracted.
Bauxite is primary ore of an aluminium metal. it doesn't have definite or specific chemical composition. This is because it contains mixture of hydrous aluminum oxide
, aluminum hydroxides
, insoluble materials like hematite, quartz ,geothite ,magnetite etc.
From the given options the most appropriate statement which is correct about the bauxite is 'It does not have a definite chemical composition'.
Hence, the correct option Is (D).
Answer:
Option E, Half life = 
Explanation:
For a first order reaction, rate constant and half-life is related as:
Where,
= Half life
k = Rate constant
Rate constant given = 
So, the correct option is option E.
Answer:metres
Explanation:It would be best to measure the length of an object in metric system such as millimeter, centimeter, mere etc..
An element is a pure substance that cannot be separated or divided into simpler substances by any method (physical or chemical). The four common elements in all the living organisms are carbon, oxygen, hydrogen, nitrogen.
Thus, the four elements that make up about 96 % of body matter are carbon, oxygen, hydrogen, nitrogen (c).
It is about equal to the mass of the neutron. So, most people just say that they have the same mass.
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