Apsara G. answered • 01/10/20

Experienced Chemistry instructor with Ph. D.

Hello Zeee, this is a cool problem. Let's break this up into steps:

a. 6.0 x 10^{-3} ml solution is injected and is 50% by volume of HCOOH

So the ant injects HCOOH that makes up half this volume of solution which means 3.0 x 10^{-3} mL of HCOOH

The ant injects only 80% of its original amount of HCOOH.

If this amount is 3.0 x 10-3, then then the original amount is

3.0 x 10^{-3} x 100/80 = 3.75 x 10^{-3 }mL. This is the amount in a typical ant

b. To make 1 L of HCOOH, use a ratio-proportion concept: (convert L to mL first, 1 L is 1000 mL)

To make 3.75 x 10^{-3} ----------> 1 ant

To make 1000 mL -----------> 1000/ 3.75 x 10^{-3} = 2.6 x 10^{5} ants

HCOOH + NaHCO_{3} --> HCOONa + CO_{2} + H_{2}O

Check if equation is balanced. (It already is)

c. In order to determine moles we need mass first

density = mass/volume. So, mass = density x volume

mass of HCOOH = density x volume

= 1.2 g/mL x 3.0 x 10^{-3}mL = 0.0036 g or 3.6 x 10^{-3} g

Next, calculate formula mass of HCOOH. 2 H, 1 C and 2 O make 46.02 g/mol

mol HCOOH = 0.0036 g

---------------

46.02 g/mol

= 7.8 x 10^{-5 } mol (using only 2 sig. fig)

Since HCOOH and NaHCO_{3} react in a 1 : 1 ratio (the balanced equation has 1 as coefficent for both)

we need the same amount of NaHCO_{3} i.e 7.8 x 10^{-5} mol

To calculate mass, we need formula mass of baking soda.

1 Na, 1 H, 1 C 3 O atomic masses add to ( 22.99 + 1.0 + 12.0 + 48.0 ) = 84.0 g

Multiply mol with formula mass to get actual mass

7.8 x 10^{-3} x 84.0 = 0.6652 g or 0.66 g of baking soda

Next time an ant bites, I will make sure to keep some baking soda handy!

Stanton D.

Reference to fire ants: "The painful sting of the fire ant may be familiar to many Americans, but the proteins that make up the potent venom have remained largely unknown. Researchers have now used mass spectrometry to identify 46 proteins in the venom of Solenopsis invicta, an invasive species of fire ant (J. Proteome Res., DOI: 10.1021/pr300451g). They say the proteins could inspire drug discovery."01/10/20

Stanton D.

Boy, I don't know what the text editor problem is today!01/10/20

Stanton D.

Just sayin' -- anyone who distills 2.6 * 10^5 ants to get a liter of formic acid is around the bend. And, not all ants inject formic acid, some just bite, and some inject other toxins as well (fire ants, e.g.). One thing is certain -- if you have 10^5 fire ants out there, you won't have any problems with moles (the mammal type).01/10/20