Answer:
3. Tails of phospholipids are hydrophobic.
Explanation:
According to the fluid mosaic model, the plasma or cell membrane contains components such as: proteins, phospholipids etc. The phospholipid forms a layer called PHOSPHOLIPID LAYER, which comprises of a phosphate head and a fatty acid (lipid) tail.
The phosphate head is HYDROPHILIC i.e. water-logging while the fatty acid/lipid tail is HYDROPHOBIC i.e. water-fearing. Hence, according to this question, it is TRUE that the tails of phospholipids are hydrophobic.
Note: Phospholipid layer, which are selectively-permeable i.e do not allow the passage of molecules, allows the passage/diffusion of small molecules like oxygen gas.
c. the ocean water was salty and rich in dissolved oxygen
Answer:
The answer is A. Chemical
Explanation:
Have a nice day
Remember that:
number of moles = mass/molar mass
First, we get the molar mass of the nitrogen gas molecule:
It is known the the nitrogen gas is composed of two nitrogen atoms, each with molar mass 14 gm (from the periodic table)
Therefore, molar mass of nitrogen gas = 14 x 2 = 28 gm
Second we calculate the mass of the precipitate:
we have number of moles = 0.03 moles (given)
and molar mass = 28 gm (calculated)
Using the equation mentioned before,
mass = number of moles x molar mass = 0.03 x 28 = 0.84 gm
Answer: hydroxide ions
Explanation:
According to the Arrhenius concept, an acid is a substance that ionizes in the water to give hydronium ion or hydrogen ion and a bases is a substance that ionizes in the water to give hydroxide ion .
According to the Bronsted Lowry conjugate acid-base theory, an acid is defined as a substance which donates protons and a base is defined as a substance which accepts protons.
According to the Lewis concept, an acid is defined as a substance that accepts electron pairs and base is defined as a substance which donates electron pairs.
As KOH can give hydroxide ions on dissociation , it is considered as arrhenius base.
