A sample of 0.1687 g of an unknown monoprotic acid was dissolved in 25.0 mL of water and titrated with 0.1150 M NaOH. The acid req uired 15.5 mL of base to reach the equivalence point. What is the molar mass of the acid?

Very short pulses of high-intensity laser beams are used to repair detached portions of the retina of the eye. The brief pulses of energy absorbed by the retina weld the detached portions back into place. In one such procedure, a laser beam has a wavelength of 810 nm and delivers 250 mW of power spread over a circular spot $510 \mu m$ in diameter. The vitreous humor (the transparent fluid that fills most of the eye) has an index of refraction of 1.34. (a) If the laser pulses are each 1.50 ms long, how much energy is delivered to the retina with each pulse? (b) What average pressure would the pulse of the laser beam exert at normal incidence on a surface in air if the beam is fully absorbed? (c) What are the wavelength and frequency of the laser light inside the vitreous humor of the eye? (d) What are the maximum values of the electric and magnetic fields in the laser beam?

A $0.105$-g sample of a diprotic acid of unknown molar mass is dissolved in water and titrated with $0.1288$ $\mathrm{M}$ $\mathrm{NaOH}$. The equivalence point is reached after adding $15.2 \mathrm{~mL}$ of base. What is the molar mass of the unknown acid?

A $0.125$-g sample of a monoprotic acid of unknown molar mass is dissolved in water and titrated with $0.1003 \mathrm{M} \mathrm{NaOH}$. The equivalence point is reached after adding $20.77 \mathrm{~mL}$ of base. What is the molar mass of the unknown acid?

Very short pulses of high-intensity laser beams are used to repair detached portions of the retina of the eye. The brief pulses of energy absorbed by the retina weld the detached portions back into place. In one such procedure, a laser beam has a wavelength of $810 \mathrm{~nm}$ and delivers $250 \mathrm{~mW}$ of power spread over a circular spot $510 \mu \mathrm{m}$ in diameter. The vitreous humor (the transparent fluid that fills most of the eye) has an index of refraction of 1.34. (d) What are the maximum values of the electric and magnetic fields in the laser beam?

Very short pulses of high-intensity laser beams are used to repair detached portions of the retina of the eye. The brief pulses of energy absorbed by the retina weld the detached portions back into place. In one such procedure, a laser beam has a wavelength of $810 \mathrm{~nm}$ and delivers $250 \mathrm{~mW}$ of power spread over a circular spot $510 \mu \mathrm{m}$ in diameter. The vitreous humor (the transparent fluid that fills most of the eye) has an index of refraction of 1.34.(b) What average pressure would the pulse of the laser beam exert at normal incidence on a surface in air if the beam is fully absorbed?

Determine whether or not each mixture is a buffer.

(a) $\mathrm{HCl}$ and $\mathrm{HF}$

(b) $\mathrm{NaOH}$ and $\mathrm{NH}_3$

(c) $\mathrm{HF}$ and $\mathrm{NaF}$

(d) $\mathrm{HC}_2 \mathrm{H}_3 \mathrm{O}_2$ and $\mathrm{KC}_2 \mathrm{H}_3 \mathrm{O}_2$

Describe the pattern in the sequence. Then find the next two terms of the sequence. 9, 15, 21, 27, ...

Determine the $\mathrm{pH}$ of each solution and classify it as acidic, basic, or neutral.

(a) $\mathrm{pOH}=12.5$

(b) $\mathrm{pOH}=5.5$

(c) $\mathrm{pOH}=0.55$

(d) $\mathrm{pOH}=7.98$

A 3.664-g sample of a monoprotic acid was dissolved in water. It took 20.27 mL of a 0.1578 M NaOH solution to neutralize the acid. Calculate the molar mass of the acid.

Cocaine is a weak organic base whose molecular formula is $C_{17}H_{21}NO_4.$ An aqueous solution of cocaine was found to have a pH of 8.53 and an osmotic pressure of 52.7 torr at $15 ^ { \circ } \mathrm { C }$ Calculate $K_b$ for cocaine.

In the 25-ft Space Simulator facility at NASA's Jet Propulsion Laboratory, a bank of overhead are lamps can produce light of intensity $2500 \mathrm{~W} / \mathrm{m}^2$ at the floor of the facility. (This simulates the intensity of sunlight near the planet Venus.) Find the average radiation pressure (in pascals and in atmospheres) on (c) Find the average momentum density (momentum per unit volume) in the light at the floor.

In the 25-ft Space Simulator facility at NASA’s Jet Propulsion Laboratory, a bank of overhead arc lamps can produce light of intensity $2500 \mathrm{W} / \mathrm{m}^{2}$ at the floor of the facility. (This simulates the intensity of sunlight near the planet Venus.) Find the average radiation pressure (in pascals and in atmospheres) on (a) a totally absorbing section of the floor and (b) a totally reflecting section of the floor. (c) Find the average momentum density (momentum per unit volume) in the light at the floor.

To what volume should you dilute 50.0 mL of a 12 M stock $HNO_3$ solution to obtain a 0.100 M $HNO_3$ solution?