What is 3.311 x 10^24 in 2 sig figs?

A. 3.311 x 10^24

B. 3.0 x 10^24

C. 3.31 x 10^24

D. 3.3 x 10^24

D. 3.3 x 10^24

Explanation:

In a number representing a measurement, the significant figure are those digits that have a meaningful contribution to specify the resolution of the measurement.

When a number is written in scientific notation, it is written as:

where

m is the base

n is the exponent

When a number is written in this form, the number of significant figures is the number of digits contained in .

In this problem, our number is initially written as

We see that here "m" contains 4 digits, so here we have 4 significant figures.

In order to reduce it to 2 significant figures, we have to rewrite 3.311 as 3.3, therefore the new number will be:

Which is option D.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.