<h3><u>Answer;</u></h3>
<em>-49 °C</em>
<h3><u>Explanation and solution;</u></h3>
- Considering the fact that, the specific heat capacity of aluminum is 0.903 J/g x C, and the heat of vaporization of water at 25 C is 44.0 KJ/mol.
Moles water = 0.48 g / 18.02 g/mol
=0.0266 moles
<em>Heat lost by water</em> = 0.0266 mol x 44.0 kJ/mol
=1.17 kJ => 1170 J
<em>But heat lost =heat gained</em>
<em>Therefore;</em> Heat gained by aluminium = 1170 J
1170 = 55 x 0.903 ( T - 25) = 49.7 T - 1242
1170 + 1242 = 49.7 T
T = 48.5 °C ( 49 °C <em>at two significant figures)</em>
<em>Hence</em>, final temperature = 49 °C
<span>True. Acid rain is formed when compounds released during the burning of fossil fuels, such as sulfur dioxide and nitrous oxide, dissolve in water droplets in clouds. These then fall as rain as part of the water cycle. While some rain is naturally acidic, human activities, like burning fossil fuels, have made it worse.</span>
The termination step of the free-radical chlorination of methane is the most stable one among all three steps.
The free-radical substitution reaction between chlorine and methane features three major steps:
Initiation, during which chlorine molecules undergo homolytic fission to produce chlorine free radicals. Ultraviolet radiations are typically applied to supply the energy required for breaking the chlorine-chlorine single bonds. The initiation step is thus <em>endothermic</em>.
Propagation, a process in which chlorine free radicals react with methane molecules and remove a hydrogen atom from the alkane to produce hydrogen chloride and an alkyl radical e.g., . The carbon-containing free radical would react with chlorine molecules to produce chloromethane and yet another chlorine free radical. This process can well repeat itself to chlorinate a significant number of methane molecules.
Termination. Free radicals combine to produce molecules. For example, two chlorine free radicals would combine to produce a chlorine molecule, whereas two alkyl free radicals would combine to produce an alkane with two-carbon atoms in its backbone.
Chemical processes that increase the stability of a substance reduces its chemical potential energy. Energy conserves, thus such processes would also release energy equal to the potential energy lost in quantity. Free radicals are unstable and- as seen in the propagation step- compete readily with neutral molecules for their electrons. The propagation step keeps the number of free radicals constant and is therefore more exothermic than the initiation step. The termination step reduces the number of free radicals, increase the stability of the system by the greatest extent, and is therefore the most exothermic step among the three.
Answer:
compound
Explanation:
When two distinct elements are chemically combined—i.e., chemical bonds form between their atoms—the result is called a chemical compound. Most elements on Earth bond with other elements to form chemical compounds, such as sodium (Na) and Chloride (Cl), which combine to form table salt (NaCl).