Answer:
Explanation:
The second one is quite simple. CH4 (methane) is the main component for natural gas. It is used to heat houses in many many areas. It it heats a house, it must give off heat. It is exothermic.
The first one is much less common and hard to reason. I think it is easier to see the reverse reaction
O2 ===> 2O
O2 is a fairly stable molecule. It takes energy to break the molecules apart. That makes this reaction endothermic.
So the reaction you are given is just the opposite. It must be exothermic.
2O ===> O2 must be exothermic.
Answer:
32.25 J
Explanation:
Heat, H = ?
Mass, m = 5g = 5 / 1000 = 0.005 Kg
Initial Temperature = 75.0° C
Final Temperature = 25.0° C
Temperature change, ΔT = Final - Initial = 50° C
Specific heat capacity of lead, C = 129 (J/kg°C)
The relationship between these quantities is given by the equation
H = mCΔT
H = 0.005 * 129 * 50
H = 32.25 J
Answer:
B
Explanation:
Because the sharpener is attached to an electrical outlet
Given that the reactants are the very consituents (elements) of the final compound, the enthalpy change of this reaction is the same heat of formation, Hf.
That means that the enthalpy chage for the reaction is -296.8 kj/mol
Tincture of iodine has antiseptic properties and is made by dissolving iodine crystals in alcohol.
<h3>What are antiseptics?</h3>
Antiseptics are substance which prevent or stops the growth of microorganisms.
Microorganisms have been known to cause diseases, therefore the application of antiseptics are useful to prevent diseases.
An example of an antiseptic is tincture of iodine.
Tincture of iodine is prepared by dissolving iodine crystals in alcohol.
In conclusion, antiseptics are useful in the prevention of diseases by microorganism. An example of an antiseptic is tincture of iodine.
Learn more about tincture of iodine at: brainly.com/question/3209701
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