Answer:
Substance 4
Explanation:
Density is defined as mass per unit volume. A substance floats in another when its density is less than that of the substance on which it floats.
If an object is immersed in a denser liquid, it will sink
Since the density of water is 1 g/cm^3, any substance whose density is less than that of water will float in it.
If we look at the table, substance 4 has a density of 0.5g/cm^3. Hence, substance 4 is expected to float in water.
Answer: The concentration of hydroxide ions at this temperature is 
Explanation:
When an expression is formed by taking the product of concentration of ions raised to the power of their stoichiometric coefficients in the solution of a salt is known as ionic product.
The ionic product for water is written as:
![K_w=[H^+][OH^-]](https://tex.z-dn.net/?f=K_w%3D%5BH%5E%2B%5D%5BOH%5E-%5D)
![5.13\times 10^{-13}=[H^+][OH^-]](https://tex.z-dn.net/?f=5.13%5Ctimes%2010%5E%7B-13%7D%3D%5BH%5E%2B%5D%5BOH%5E-%5D)
As ![[H^+]=[OH^-]](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D%5BOH%5E-%5D)


The concentration of hydroxide ions at this temperature is 
Answer:
Water
Explanation:
Water had the strongest intermolecular forces and evaporated most slowly. ... Water evaporates most slowly because its molecules are attracted to one another by hydrogen bonding.