If 30 kJ of heat flows out of a system and 15 kJ of work is done by the system, then what is the change in internal energy?  Express your answer in kJ.

The heat of fusion for ice at 0°C is 333.7 kJ/kg, the specific heat of water 4.186 kJ/kg °C, and the heat of vaporization of water at 100°C is 2,256 kJ/kg. What is the energy needed to vaporize 100 grams of ice at starting at 0°C?  Express your answer in kJ.

Assume that helium behaves as an ideal monatomic gas. If 2 moles of helium undergo a temperature increase of 100 K at constant pressure, how much work is done by the gas?

What must be the distance in meters between point charge q1 = 22.0 µC and point charge q2 = -61.2 µC for the electrostatic force between them to have a magnitude of 5.76 N?

The figure displays a closed cycle for a gas (the figure is not drawn to scale). The change in the internal energy of the gas as it moves from a to c along the path abc is -164 J. As it moves from c to d, 178 J must be transferred to it as heat. An additional transfer of 77.5 J to it as heat is needed as it moves from d to a. How much work is done by the gas as it moves from c to d?

The heat capacity at constant volume and the heat capacity at constant pressure have different values because:

A sample of an ideal gas is taken through the cyclic process abca shown in the figure. The scale of the vertical axis is set by pb = 7.79 kPa and pac = 4.12 kPa. At point a, T = 189 K.  Find the temperature of the gas at point c.Assume Va = 1.86 m3, Vbc = 4.05 m3.

The coefficient of linear expansion of iron is 10–5 per C°. The volume of an iron cube, 5 cm on edge, will increase by what amount if it is heated from 10°C to 60°C. (express your answer in cm3)

What are potential consequences for dental assistants in California who do not follow infection control laws?

Which agency issues guidelines for infection control in dental healthcare settings?