Temperature of an iron block decreases from 850C to 250C. Calculate the heat lost by the block with a mass of 1,200g. (heat capacity of iron=0.115cal/g. °C) O a 1,980 Calories 88,200 Calories 8,280 Calories 29,000 Calories Question 15 A cup of water will freeze at 0°C. Which statement best describes this phase change? O a Endothermic, energy is released. O b Exothermic, energy is released. Exothermic, energy is absorbed. Endothermic, energy is absorbed.

Temperature of an iron block decreases from 850C to 250C. Calculate the heat lost by the block with a mass of 1,200g. (heat capacity of iron=0.115cal/g. °C) O a 1,980 Calories 88,200 Calories 8,280 Calories 29,000 Calories Question 15 A cup of water will freeze at 0°C. Which statement best describes this phase change? O a Endothermic, energy is released. O b Exothermic, energy is released. Exothermic, energy is absorbed. Endothermic, energy is absorbed.

Introductory Chemistry: A Foundation

9th Edition

ISBN:9781337399425

Author:Steven S. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Donald J. DeCoste

Chapter10: Energy

Section: Chapter Questions

Problem 44QAP: When ethanol (grain alcohol, is burned in oxygen, approximately 1360 kJ of heat energy is released...

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1. Which of the following processes requires the largest input of energy as heat? raising the temperature of 100 g of water by 1.0 °C vaporization of 0.10 g of water at 100 °C melting 1.0 g of ice at 0 °C warming 1.0 g of ice from −50 °C to 0 °C (specific heat of ice = 2.06 J/g · K)
The enthalpy change when 1 mol methane (CH4) is burned is 890 kJ. It takes 44.0 kJ to vaporize 1 mol water. What mass of methane must be burned to provide the heat needed to vaporize 1.00 g water?
A student is asked to calculate the amount of heat involved in changing 10.0 g of liquid bromine at room temperature (22.5C) to vapor at 59.0C.To do this, one must use Tables 8.1 and 8.2 for information on the specific heat, boiling point, and heat of vaporization of bromine. In addition, the following step-wise process must be followed. (a) Calculate H for: Br2(l,22.5C)Br2(l,59.0C) (b) Calculate H for: Br2(l,59.0C)Br2(g,59.0C) (c) Using Hess's law, calculate H for: Br2(l,22.5C)Br2(g,59.0C)
How much heat, in joules and in calories, is required to heat a 28.4-g (1-oz) ice cube from 23.0 C to 1.0 C?
Equal masses of liquid A, initially at 100C, and liquid B, initially at 50C, are combined in an insulated container. The final temperature of the mixture is 80C. All the heat flow occurs between the two liquids. The two liquids do not react with each other. Is the specific heat of liquid A larger than, equal to, or smaller than the specific heat of liquid B?
9.102 A runner generates 418 kJ of energy per kilometer from the cellular oxidation of food. The runner's body must dissipate this heat or the body will overheat. Suppose that sweat evaporation is the only important cooling mechanism. If you estimate the enthalpy of evaporation of water as 44 kJ/mol and assume that sweat can he treated as water, describe how you would estimate the volume of sweat that would have to be evaporated if the runner runs a 10-km race.
9.45 What happens to the temperature of a material as it undergoes an endothermic phase change? If heat is added, how can the temperature behave in this manner?
When ethanol (grain alcohol, is burned in oxygen, approximately 1360 kJ of heat energy is released per mole of ethanol. mg src=Images/HTML_99425-10-44QAP_image002.jpg alt="" align="top"/> What quantity of heat is released for each gram of ethanol burned? i>What is for the reaction as written? How much heat is released when sufficient ethanol is burned so as to produce 1 mole of water vapor?
The heat of neutralization, Hneut, can be defined as the amount of heat released (or absorbed), q, per mole of acid (or base) neutralized. Hneut for nitric acid is -52 kJ/mol HNO3. At 27.3C, 50.00 mL of 0.743M HNO3 is neutralized by 1.00 M Sr(OH)2 in a coffee-cup calorimeter. (a) How many mL of Sr(OH)2 were used in the neutralization? (b) What is the final temperature of the resulting solution? (Use the assumptions in Question 11.)