Answer:
A molecule is tetrahedral if the central atom has four bonds and no lone pairs.
Explanation:
A typical example is a molecule of methane (see image).
The electron pairs in the bonds repel the electrons in the other bonds, so they all try to get as far from each other as possible.
They can do this if the bonds point to the corners of a tetrahedron, with bond angles of 109.5°.
Join or be joined securely to something else, typically by means of an adhesive substance, heat, or pressure.
Explanation:
1. Sedimentation and decantation cannot be used for all types of mixtures.
Decantation is a separation technique in which is used to separate immiscible liquids or mixtures containing liquid and solids within them.
In decantation, gravity is used to bring the denser materials to settle at the bottom.
For homogenous mixtures, it is not possible to use decantation. A solution of sugar and water will not decant.
2. Yes, mass of an object reduces the settling time of such object in a mixture.
The higher the mass, the faster the rate of settling. Also, as we know, mass is directly proportional to density. A body with a high density will settle faster in solution.
The answer should be:
KOH (aq) + HCl (aq) --> KCl (aq) + H20 (l).
KOH is a base, because OH can accept a H+.
HCl is an acid because it can donate a H+.
In general, bases are : OH-, and acids are : H+.
