Answer:
here:
Explanation:
The changes in temperature caused by a reaction, combined with the values of the specific heat and the mass of the reacting system, makes it possible to determine the heat of reaction.
Heat energy can be measured by observing how the temperature of a known mass of water (or other substance) changes when heat is added or removed. This is basically how most heats of reaction are determined. The reaction is carried out in some insulated container, where the heat absorbed or evolved by the reaction causes the temperature of the contents to change. This temperature change is measured and the amount of heat that caused the change is calculated by multiplying the temperature change by the heat capacity of the system.
The apparatus used to measure the temperature change for a reacting system is called a calorimeter (that is, a calorie meter). The science of using such a device and the data obtained with it is called calorimetry. The design of a calorimeter is not standard and different calorimeters are used for the amount of precision required. One very simple design used in many general chemistry labs is the styrofoam "coffee cup" calorimeter, which usually consists of two nested styrofoam cups.
When a reaction occurs at constant pressure inside a Styrofoam coffee-cup calorimeter, the enthalpy change involves heat, and little heat is lost to the lab (or gained from it). If the reaction evolves heat, for example, very nearly all of it stays inside the calorimeter, the amount of heat absorbed or evolved by the reaction is calculated.
Answer:
14
Explanation:
Given parameters:
Number of protons = 6
Number of electrons = 6
Number of neutrons = 8
Unknown:
Mass number = ?
Solution:
The mass number of an atom is the sum of protons and neutrons in an atom;
Mass number = number of protons + number of neutrons
Mass number = 6 + 8 = 14
The oxidation state of Chromium chloride (III) is +3
How can we find the answer?
First of all write down what you know about the molecule:
1: The molecule hasn't got an electric charge (is not an ione), this means that either positive and negative charges of its atoms are balanced (we have the same number of positve and negative charges)
2: Since it's a salt, where the metal is chromium and the non metal is the alogen Chlorine, we know that the negative charge belogns to the non metal element because of its elettronegativity, therefore the positive charge belongs to the metale element (chromium).
3: when chlorin forms binary salts its oxidation state is always -1 (you can find out this info in a periodic table)
In <span>CrC<span>l3</span></span> we have 3 chlorine atoms where each of them carrys 1 negative charge, so the total amount of negative charges is -3
Since the charges are balanced, the question is: Which is the positive charge that Chromium must carry in order to balance 3 negative charges?
The answer comes out to +3
Answer:
D
) feedback
Explanation:
When we use an air conditioner, it get turn off when reaches its required temperature and when the house warm up the air conditioning unit turns on again, that is an example of feedback.
The given condition is an example of negative feedback because in negative feedback, any change in the input is opposed by generating an output. Here also, warming up of house (change in one direction) allows the air conditioning unit turns on and it gives cool air (opposing that change).
Hence, the correct option is "D".
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