How do we know that the chain of carbon atoms in the straight chain alkanes actually must exist in a zig-zag arrangement? What are the bond angles around the carbon atoms in an alkane?

Measurement in Chemistry Always begins with a number followed by a unit of measure. Ex. 35 m, 0.25 L, 225 lbs., 3.4 hrs. Scientific Notation- Used to write very large or very small numbers, particularly useful in Chem. When written in Sci. notation, comes in three parts- 3.235*10^23 Mantissa(greater than one but less than ten)=3.235 Base(usually ten)=10 (wow that’s funny) Exponent(number that tells how many times the base is multiplied by itself)=23 Steps in Sci Notation 1. Start with number- 3452 .045767 2. Write in decimal point if needed. 3452. .045767 3. Move decimal point so that only one non-zero digit is to the left of the decimal. 3.452 4.5787 4. If the decimal was moved left, the exponent will be positive. If it was moved right, it will be negatnve.