Guidewords for the word “serpent” may be a.
Serbia and service
c.
Seltzer and Saturday
b.
Seattle and section
d.
Solitude and second
THE CORRECT ONE IS A

A. Serbia and service

Explanation:

A guide word is a word written on top of a page to indicate the first or last word entry on that page. For example in a dictionary, they indicate the alphabetical first and last words on the page.

In this example; the word ' serpent ' note the first three letters to guide you in the words that are on that page;

In this case : Serbia  and Service.

  the grams     of oxygen gas   that can be produced     is 20.6   grams of o₂

calculation

2liclo₃ →   2 licl + 3 o₂

step 1:   find the moles of liclo₃

moles = mass÷ molar mass

from periodic table the molar mass of liclo₃ =6.9 +35.5   +(16 x3) =90.4 g/mol

moles=38.7 g÷90.4 g/mol=0.4281   moles

step 2:   use the   mole ratio   to calculate the moles of o2

from equation above, liclo₃: o₂   is 2: 3  

therefore the moles of   o₂=0.4281 moles x3/2 =0.6422   moles

step 3: find mass   of o₂

mass= moles x molar mass

from periodic table the   molar mass of   o₂ = 16 x2= 32 g/mol

mass=0.6422   moles   x   32 g/mol = 20.6 grams of o₂

mistakes are ok