Determine the number of significant figures for each. a) 65.74 b) 60.009 c) 66_ d) 65.750

a) 65.74 = 4 significant figures

b) 60.009 = 5 significant figures

c) 66_ = 2 significant figures

d) 65.750 = 5 significant figures

Explanation:

Significant figures or digits is defined as the total number of digits in a number that have meaning and contribute to the precision of the given number.    

a) 65.74 = 4 significant figures, all the non-zero figures are considered significant.

b) 60.009 = 5 significant figures, zeros present between non-zero figures are significant.

c) 66_ = 2 significant figures, all the non-zero figures are considered significant.

d) 65.750 = 5 significant figures, all the non-zero figures and the trailing zero after the decimal are significant.                                      

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

the answer is c

tell me if wrong