Answer:
See below
Step-by-step explanation:
(a) Shape
The formula for water is H-O-H.
The central O atom has four electron pairs around it. They try to get as far from each other as possible, so they point toward the corners of a tetrahedron.
Only two of the pairs have a hydrogen atom attached, so water has a bent shape. The H-O-H bond angle is about 104°.
(b) Chemical magnet
The O atom has a greater attraction than H for the shared electrons in the O-H bonds, so the electrons spend more time near the O.
This gives the O atom a partial negative charge (pink in the diagram) and the H atoms a partial positive charge (blue).
The water molecule acts like a chemical magnet because its negative end attracts the positive ends of other molecules, while its positive ends attract the negative ends of other molecules.
Answer: C
Explanation:
Some poly nuclear aromatic hydrocarbons are not carcinogenic in themselves. However, when these are made to interact with living cells, enzymes in the cells could convert the polynuclear aromatic hydrocarbon into a carcinogenic material such as benzo-[a]-pyrene. This can now interact adversely with the deoxyribonucleic acid of living cells leading to genetic mutation, that is, irreversible changes in the genes of organisms.
5 bromo 1.1.1 -trichloro -5 ethyl 2.3 dimethyl heptane
Unit ppm stands for parts per million. in terms of mass, ppm is equivalent to mg/kg.
since 1 kg is 10⁻⁶ mg, 1 kg is equivalent to million mg.
therefore mg/kg is also ppm.
there are 1.3 g of Ca ions in 3100 kg
if 3100 kg contains - 1.3 g of Ca
then 1 kg contains - 1.3 g / 3100 kg
then Ca ions - 0.42 x 10⁻³ g/kg
Ca ion concentration - 0.42 mg/kg
therefore Ca ion concentration is 0.42 ppm