Answer:
A. + 6.
B. + 3.
Explanation:
<em>A. K₂CrO₄:</em>
- To calculate the oxidation no. of an element in a compound:
<em>We have that the sum of the oxidation no. of different elements in the compound multiplied by its no. is equal to the overall charge of the compound.</em>
∵ 2(oxidation no. of K) + (oxidation no. of Cr) + 4(oxidation no. of O) = 0.
oxidation no. of K = + 1, oxidation no. of O = - 2.
∴ 2(+ 1) + (oxidation no. of Cr) +4(- 2) = 0.
∴ 2 + (oxidation no. of Cr) - 8 = 0.
∴ (oxidation no. of Cr) - 6 = 0.
<em>∴ oxidation no. of Cr = + 6.</em>
<em></em>
<em>B. Cr₂O₃:</em>
∵ 2(oxidation no. of Cr) + 3(oxidation no. of O) = 0.
oxidation no. of O = - 2.
∴ 2(oxidation no. of Cr) + 3(- 2) = 0.
∴ 2(oxidation no. of Cr) - 6 = 0.
∴ 2(oxidation no. of Cr) = + 6.
<em>∴ (oxidation no. of Cr) = + 6/2 = + 3.</em>
Answer:
Chemical Change
Explanation:
This is a chemical change since the chemical structure of the components in the cheesecake changes when it is baked. This means that you can't make a baked cheesecake unbaked.
Taking into account the animals and the landscape being mentioned, we can confirm that the combination of these forms<u><em> part of an </em></u><u><em>ecosystem</em></u><u><em>.</em></u>
An ecosystem is described as an area consisting of:
- Plants
- Animals
- Bacteria
- Weather
- Landscape
and many other factors, which all work together to form a small pocket of life.
Ecosystems are described as containing both living and non-living elements, meaning biotic and non-biotic parts. A community or population, on the other hand, <u>are used to consider only the </u><u>biotic </u><u>or </u><u>living factors </u><u>of an </u><u>ecosystem</u><u>. </u>Therefore, since the question includes the rock bottom (a<em><u> non-biotic factor</u></em>) as a part of the makeup, the only correct grouping is that of an ecosystem.
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Answer:
C
Explanation:
Answer: C. A thoroughly tested and widely accepted explanation. Explanation: A scientific theory is a coherent statement or set of ideas that explains observed facts or phenomenon and are thoroughly tested and widely accepted.
Answer:
(2) Boiling point order: Methanol (highest) > Methanal > Methane (weakest)
(3) Boiling point of alcohol will be higher than ester molecules
Explanation:
(2) Methane is a non-polar molecule. Hence only weakest van der waal inter molecular force is present between methane molecules.
Methanal is polar molecule due to presence of polar aldehyde group. hence weaker dipole-dipole inter molecular force is present between methanal molecules.
Methanol is a polar protic molecule. Hence strongest H-bonding force act between methanol molecules.
The stronger the inter molecular force, the higher will be boiling point.
Boiling point order: Methanol (highest) > Methanal > Methane (weakest)
(3) An alcohol is a polar protic molecule. Hence strongest H-bonding force exist between alcohol molecules.
An ester is polar molecule. Therefore weaker dipole-dipole inter molecular force is present between ester molecules.
So boiling point of alcohol will be higher than ester molecules.
