Answer:
Rock
Explanation:
Rock -
It refers to the naturally occuring mass of mineral , with a uniform chemical composition , is referred to as a rock .
In the crust of the Earth , the composition is by the igneous rocks .
<u>There are three main type of rocks , i.e. , </u>
- sedimentary rocks ,
- metamorphic rocks ,
- igneous rocks .
Hence , from the given information of the question ,
The correct term is rock.
The question is incomplete, the remaining part of the question is
Which of the above occurs for each of the following circumstances?
A 50-milliliter sample of a 2-molar Cd(NO3)2 solution is added to the left beaker.
Answer:
Voltage decreases but remains > zero.
Explanation:
Given the balanced redox reaction equation:
2Ag^+(aq) + Cd(s) ---------------> 2 Ag(s) + Cd^2+(aq)
Concentration affects the cell voltage according to Nernst equation. Change in concentration must lead to a change in cell Voltage.
As the concentration of the Cd(NO3)2 solution is increased, voltage decreases because of the increase in the concentration values but voltages remains above zero.
Answer:
The main competing reaction when a primary alkyl halide is treated with alcoholic potassium hydroxide is SN2 substitution.
Explanation:
The relative percentage of products of the reaction between an alkyl halide and alcoholic potassium hydroxide generally depends on the structure of the primary alkylhalide. The attacking nucleophile/base in this reaction is the alkoxide ion. Substitution by SN2 mechanism is a major competing reaction in the elimination reaction intended.
A more branched alkyl halide will yield an alkene product due to steric hindrance, similarly, a good nucleophile such as the alkoxide ion may favour SN2 substitution over the intended elimination (E2) reaction.
Both SN2 and E2 are concerted reaction mechanisms. They do not depend on the formation of a carbocation intermediate. Primary alkyl halides generally experience less steric hindrance in the transition state and do not form stable carbocations hence they cannot undergo E1 or SN1 reactions.
SN2 substitution cannot occur in a tertiary alkyl halides because the stability of tertiary carbocations favours the formation of a carbocation intermediate. The formation of this carbocation intermediate will lead to an SN1 or E1 mechanism. SN2 reactions is never observed for a tertiary alkyl halide due to steric crowding of the transition state. Also, with strong bases such as the alkoxide ion, elimination becomes the main reaction of tertiary alkyl halides.
Sulfur, selenium, and tellurium
Physical changes occur when the properties of a substance are retained and/or the materials can be recovered after the change. Chemical changes involve the formation of a new substance. Formation of a gas, solid, light, or heat are possible evidence of chemical change.
