Hydrogen gives off 120 . J / g of energy when burned in oxygen, and methane gives off 50 . J/g u

Hydrogen gives off 120 . J / g of energy when burned in...

Key Concepts

Specific Heat Capacity

Specific heat capacity is a property of a material that indicates the amount of heat energy required to raise the temperature of one gram of the substance by one degree Celsius. It is essential in calculating temperature changes in calorimetry experiments, as it relates the amount of heat transferred to the temperature change of the material.

Energy Conservation in Calorimetry

The principle of energy conservation in calorimetry states that the total energy released by a reaction is equal to the total energy absorbed by the substances involved, assuming there are no losses to the surroundings. This concept allows us to calculate unknown quantities, such as final temperature, by equating the energy produced and the heat absorbed.

Calorimetry

Calorimetry is the measurement of heat transfer in physical and chemical processes. It involves using a calorimeter to determine the amount of heat absorbed or released during a reaction or phase change, under the assumption that the heat lost or gained by the system is equal to the heat gained or lost by its surroundings.

Energy per Unit Mass

Energy per unit mass refers to the amount of energy produced or required per unit mass of a substance. This concept is crucial in comparing different fuels, as it tells us how much energy will be released or needed when a given mass of fuel reacts or undergoes a process.

Combustion

Combustion is a chemical reaction that occurs when a fuel reacts with an oxidizer to release energy in the form of heat and light. In thermodynamics, combustion is typically an exothermic process, meaning that it releases heat, which can then be transferred to other materials in the system.

Transcript

00:01 Okay, so in this problem, we're given a combustion reaction, and this reaction consists of hydrogen gas and methane gas.

00:09 And we're given both the respective heats of combustion per, it's given in joules per gram of substance.

00:18 So we're going to go ahead and determine that.

00:22 Ultimately, the question is saying that we're going to run this combustion reaction and transfer the heat given off to water and they want us to figure out what is the final temperature of the water and they give us things such as mass and the initial temperature.

00:40 So we'll go ahead and figure out what that change in temperature is and then ultimately we can find the final temperature of that water.

00:47 So first of all, we're given the values hydrogen gas for every one gram that's burned in this reaction.

00:55 We have 120 joules worth of energy released and then for methane, we have for every one gram of substance burns, we have 50 joules worth of energy.

01:07 So from there, they give us 5 grams of hydrogen and 10 grams of methane are given in this reaction.

01:15 So we simply need to find those respective heats given off and just combine them together.

01:22 So we'll do that first.

01:23 Then we know how much heat was evolved.

01:26 And that's the same amount of heat that is transferred over to the water.

01:30 And again, we assume that none of that is released or lost to the environment.

01:37 And from there, this is to figure out our heat.

01:42 And then from there, we'll use q equals mc delta t.

01:46 And ultimately, we're just trying to find this guy over here.

01:51 We're trying to find out what is our delta t.

01:54 We have mass.

01:55 We have specific heat.

01:57 That's a known data quantity.

01:59 And we do have our initial temperature as well.

02:03 Our t .i.

02:04 Is 25 degrees celsius.

02:10 Okay, so we'll go back to the second screen real quick.

02:13 So we have five grams of hydrogen, and i know 120 joules will be released per one gram.

02:23 So for hydrogen, we know we have 600 joules released, and then we're given 10 grams of the methane.

02:32 That's the m down here.

02:33 M is for the methane.

02:36 And we have 50 joules per gram here...

Please give Ace some feedback