The heat required to raise the temperature of a certain mass of sample to a specific temperature change, we use the formula mCpΔT where m is mass, Cp is the specific heat of the substance and ΔT is the temperature change. In this case, we substitute and form 1.25 g x 0.057 cal/g C *20 C equal to 1.425 calories.
Enthalpy is a state function
Explanation:
The Hess's law allows us to determine the enthalpy change of a reaction because enthalpy is a state function. It does not depend on the individual path take in going from reactants to products in the reaction.
- Enthalpy changes are the heat changes accompanying physical and chemical changes.
- It is the difference between the heat content of product in the final state and the reactants.
- Enthalpy changes for some reactions are not easily measurable experimentally.
- To calculate such heat changes, we apply the Hess's law of heat summation.
- The law states that "the heat change of a reaction is the same whether it occurs in a step or several steps".
- The Hess's law is simply based on the first law of thermodynamics by which we know that energy is conserved in every system.
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Answer:
55.9 g KCl.
Explanation:
Hello there!
In this case, according to the definition of molality for the 0.500-molar solution, we need to divide the moles of solute (potassium chloride) over the kilograms of solvent as shown below:
Thus, solving for the moles of solute, we obtain:
Since the density of water is 1 kg/L, we obtain the following moles:
Next, since the molar mass of KCl is 74.5513 g/mol, the mass would be:
Regards!
When investigative officers get to a crime scene, they do not need to collect water samples.
<h3>What is a crime scene?</h3>
A crime scene is a place where an offence has been committed. It is usually cordoned off to enable investigation of the crime and the collection of samples.
When investigative officers get to a crime scene, they do not need to collect water samples.
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