You can use dimensional analysis:
Disadvantage is your answer :)
To determine the number of years for a person to live, we can divide the total number of beats in a lifetime to the number of beats per minute. We first need to check if the units are similar so we can cancel them. We do as follows:
3.1x10^9 beats / 68 beats per minute = 45588235.29 minutes ( 1hr / 60 min ) ( 1 day/24hr) ( 1 year / 365 days ) = 87 years
Hope this answers the question. Have a nice day.
The effect of an insoluble impurity, such as sand, on the observed melting point of a compound would be none. It will not depress or elevate the melting point of the compound. Instead, it would affect the reading if you are trying to determine the melting point of the compound. This is because you might be missing the actual melting point of the compound since you will be waiting for the whole sample to liquify. You would not be able to determine exactly that temperature because of the insoluble impurity would have a different melting point than that of the compound.
More than likely, your seeing a chemical reaction. The bubbles that are forming are caused by two compounds interacting with each other.