Which statement for NH3 and NF3 is false? Electronegativities: N = 3.0, H = 2.1, F = 4.0. A. Both are sp3 hybridized at nitrogen. B. The bond dipoles in NF3 are directed toward the more electronegative fluorine atoms. C. The bond dipoles of NF3 are directed toward fluorine, whereas those in NH3 are directed toward nitrogen. D. The bond dipoles in NF3 oppose the effect of the unshared pair of electrons. E. Both molecules have one unshared pair of electrons in the outer shell of nitrogen. F. The nitrogen atom can be described as utilizing sp3 hybrid orbitals in the nitrogen trifluoride molecule. G. The bond angles in NF3 are smaller than those in NH3. H. The NF3 molecule is more polar than the NH3 molecule.

A cubic container of volume 2.00 L holds 0.500 mol of nitrogen gas at a temperature of $25.0 ^ { \circ } \mathrm { C }$. What is the net force due to the nitrogen on one wall of the container? Compare that force to the sample’s weight.

A storage tank contains $21.6 \mathrm{~kg}$ of nitrogen $\left(\mathrm{N}_2\right)$ at an absolute pressure of $3.45 \mathrm{~atm}$. What will the pressure be if the nitrogen is replaced by an equal mass of $\mathrm{CO}_2$ at the same temperature?

Predict the bond angles for all bonds in the compound below:

$\mathrm{C}_2 \mathrm{H}_4$

A red blood cell count is typically about 5,000,000/$mm^3$ blood. Express this count in scientific notation.

For matrix

$$\begin{bmatrix}1&0&0\\-1&3&0\\3&2&-2\end{bmatrix}$$

, compute its eigenvalues, eigenvectors and the dimension of eigenspace.

A model used for the yield $Y$ of an agricultural crop as a function of the nitrogen level $N$ in the soil (mea- sured in appropriate units) is

$$Y = \frac { k N } { 1 + N ^ { 2 } }$$

where k is a positive constant. What nitrogen level gives the best yield?

What is the mass, in grams, of each of the following quantities of matter?

a. 0.85 mole of copper atoms

b. 0.85 mole of nickel atoms

c. 2.50 moles of nitrogen atoms

d. 2.50 moles of nitrogen molecules $\text{(N}_{2})$

Use the Born-Haber cycle to calculate the enthalpy of formation of $\mathrm{KBr}$, which crystallizes in the $\mathrm{NaCl}$ lattice. Use these data in the calculation: $\Delta H_{\text {vap }}\left(\mathrm{Br}_2\right)=29.8 \mathrm{~kJ} / \mathrm{mol} ; \mathrm{Br}_2$ bond energy $=190.2 \mathrm{~kJ} / \mathrm{mol}$; and $\Delta H_{\text {sub }}(\mathrm{K})=79 \mathrm{~kJ} / \mathrm{mol}$.

If a negative charge is moved in the same direction as the electric field lines in some region of space, does the potential energy of the negative charge increase or decrease? Explain.

Calculate V(P) at the origin P = (0, 0) if the electric charge is distributed along

$$y = x ^ { - 1 }$$

for

$$\frac { 1 } { 2 } \leq x \leq 2$$

with charge density

$$\delta ( x , y ) = x ^ { 3 } y.$$

Explain why it would be advantageous to produce a polymer with a high degree of crystallinity.

What do we mean by carrying capacity? Why is it so difficult to determine the carrying capacity of Earth?

For the bond P-Cl, indicate the positive end with $\delta^+$ and the negative end with $\delta^-$. Draw an arrow to show the dipole.