Questions

• Cactus spines are also known as modified bud scales, which are also called modified leaves.

• Cactus spines occur in clusters in the axil of leaves.

Part of the heat is conducted away by the metal table. Convection currents in air near the surface of the coffee are set up which accounts for some heat loss. Heat is also lost by radiation from the hot coffee to the surroundings. Most of the heat is lost by the last method.

You have to consider three things.

1. First, are the bonds polar?

Look at differences in electronegativity and if  it is >0.5, bonds are polar.

2. Second, does the molecule have unshared electron pairs?

If so, they generally lead to a polar molecule.

3. Third, is the molecule symmetric?

If so, then although the bonds may be polar, the symmetry cancels out the individual bond polarity and the molecule is non polar.

CF4 follows all the rules above and has a symmetric distribution of charge, making it nonpolar. The others all have asymmetric charge distributions.

Hence, CF4 represents a Non-polar molecule.

The given math puzzle follows a logic that,

1 + 4 = 5 => 1 x 4 + 1 = 5

2 + 5 = 12 => 2 x 5 + 2 = 12

3 + 6 = 21 => 3 x 6 + 3 = 21

Similarly,

8 + 11 = > 8 x 11 + 8 = 96.

Beats means the periodic increase and decrease in loudness heard when two notes of nearly the same frequency are sounded simultaneously.

From the given equation,

88x370/100 + 24x210/100 - 118 = x

=> x = 325.6 + 50.4 - 118

x = 258.