Assume a healthy hearts beats exactly 70 times per minute. If individual lives to age 85 years, estimate the number of heartbeats in their lifespan using scientific notation and the correct number of sig figs.

Given :

Number of heart beat in 1  minute , n = 70 .

The individual lives for 85 years .

To Find :

The number of heartbeats in their lifespan .

Solution :

Now , number of minutes in one hour is 60 .

One day contains 24 hours .

Therefore , minutes in one whole day :

Now , 1 year contains 365 days .

( Note : We are not considering any leap years )

Minutes in one year are :

So ,total minutes in 85 years is :

Hence , this is the required solution .

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.