An unknown mass of each of the following substances, initially at 24.0°C, absorbs 1930J of heat. The final temperature is recorded as indicated. Find the mass of each substance. a. Pyrex glass (Tf=55.1°C) Express your answer using two significant figures. m=____________g b.sand (Tf=62.1°C) Express your answer using two significant figures. m=____________g ethanol (Tf=44.0°C) water (Tf=32.0°C) Express your answer using two significant figures. m=___________g A 32.9g iron rod, initially at 21.9°C, is submerged into an unknown mass of water at 62.9°C, in an insulated container. The final temperature of the mixture upon reaching thermal equilibrium is 59.6°C. What is the mass of the water? Express your answer to two significant figures and include the appropriate units. m= m=____________g Consider the following generic reaction: A+2B?C+3D, ?H = 101kJ . Determine the value of ?H for each of the following related reactions: a. 3A+6B?3C+9D ?H = kJ b. C+3D?A+2B ?H = kJ c. 1/2C+3/2D
?1/2A+B ?H = kJ Calculate the wavelength of each of the following frequencies of electromagnetic radiation. 103.5MHz (typical frequency for FM radio broadcasting) Express your answer using four significant figures. ?1 = m 1090kHz (typical frequency for AM radio broadcasting) (assume four significant figures) Express your answer using four significant figures. ?1 = m 835.6 MHz (common frequency used for cell phone communication) Express your answer using four significant figures. ?3 = m A heat lamp produces 23.0 watts of power at a wavelength of 6.7µm . How many photons are emitted per second? (1 watt = 1 J/s) Express your answer using two significant figures. N = s-1 Calculate the de Broglie wavelength (in pm) of a hydrogen atom traveling 445m/s . Express your answer with the appropriate units. ? = An electron traveling at 2.6×105m/s has an uncertainty in its velocity of 9.25×104m/s . What is the uncertainty in its position? Express your answer with the appropriate units. ?x =