Chloride Content by Weight of Concrete. Q.: For corrosion protection, ACI 318-95, Building Code Requirements for Structural Concrete, specifies maximum water-soluble chloride ion in concrete as percent by weight of cement. What are acceptable levels when measuring chloride-ion content in existing concreteâspecifically, by weight of the concrete sample?
Plasma membranes are selectively permeable, regulating the cellâs molecular traffic. Hydrophobic (nonpolar) molecules, such as hydrocarbons, can dissolve in the lipid bilayer and. pass through the membrane rapidly. Polar molecules, such as sugars, do not cross the membrane easily. Transport Membranes Transport proteins allow passage of hydrophilic substances across the membrane.
Rating Newest Oldest. Best Answer: Yes, it is the cell membrane. Some molecules can just passively diffuse through the cell membrane. These molecules are usually smaller and non-polar. Other molecules require membrane channels to pass through the membrane.These are usually large and/or polar.ating Newest Oldest. Best Answer: Yes, it is the cell membrane. Some molecules can just passively diffuse through the cell membrane. These molecules are usually smaller and non-polar. Other molecules require membrane channels to pass through the membrane.