<span>A chemical reactions :
Involves small amounts of energy.
</span><span> Only electrons are involved.
</span><span>The mass remains the same.</span>
Answer: 10ml
In this question, you are given the liquid medicine concentration (100mg/5ml) and the doses of the medicine that must be taken(200mg). You are asked how much ml of the drug needed. Then the calculation would be:
Volume of drug needed= doses of the drug / drug concentration
Volume of drug needed= 200mg / (100mg/5ml)= 10ml
Answer: 
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The balanced chemical equation for reaction of potassium superoxide with carbon dioxide to produce oxygen and potassium carbonate will be:
<span>Answer: the average kinetic energy of the particles.
</span><span />
<span>Jusitification:
</span><span />
<span>Temperature and heat energy are closely related.
</span><span />
<span>While heat is the kinetic energy of the particles of a substance which is transferred from a hotter substance to a cooler one, the temperature is a measure of the average kinetic energy of the particles in a substance.
</span><span />
<span>The relatively high kinetic energy the particles of a warm substance is transferred to the cooler one by the motion (vibration or translation) of the atoms of molecules. The energy transferred is heat energy.</span>
The answer is 3. The releasing of energy means exothermic reaction. So the ΔH should be negative. And the greatest quantity of energy released means that the greatest number. So according to the table I, the answer is 3.
