The correct answer would be equation 4, because there are 4 Hydrogens and 2 Oxygens on each side of the equation making it balanced.
Explanation:
Yes, a chemical reaction can happen with only one substance.
A typical example of such reaction is the radioactive decay.
Radioactive decay is the loss of elementary particles from an unstable nucleus, ultimately changing the unstable element into another more stable element. .
When radioactive elements are let alone, they decompose to form stable harmless elements.
An example of radioactive decay is attached in the image below;
Answer:
The value is 
Explanation:
From the question we are told that
The molar mass of
is 
The total mass is
The uncertainty of the total mass is 
Generally the molar weight of calcium is 
The percentage of calcium in calcite is mathematically represented as


Generally the mass of each sample is mathematically represented as



Generally mass of calcium present in a single sample is mathematically represented as


The uncertainty of mass of a single sample is mathematically represented as



The uncertainty of mass of calcium in a single sample is mathematically represent

Generally the average mass of calcium in each sample is

Hydroxide ion concentrstion in bleach is higher