QUICK!! UNIT TEST...YALL KNOW THIS!<3 There are several different models that represent compounds. One type of model is shown.

The table chart is shown below a screenshot labeled "The Chart of C and H". Unless it just named itself 'Screenshot". But yall know what i mean!

What type of model is shown?

A. a structural formula

B. a chemical formula

C. a space-filling model

D. a ball-and-stick model

I believe this is a chemical formula

Explanation:

It's been a while since I've done chemistry. Sorry, this is late, and hope you still have time. Also sorry if this is wrong, but I Hope This Helps!

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.