Example: Calculate the pH of a buffer solution that initially consists of 0.0400 moles of ammonia and 0.0250 moles of ammonium ion, after 20.0 mL of 0.75 M NaOH has been added to the buffer. Ka for ammonium ion is 5.6 x 10 -10.
There are two types of bacteria. Aerobic bacteria live with oxygen, love the company of food particles in the mouth and feed on sugar. Anaerobic bacteria exist without oxygen and feed off dead skin cells and other bacteria.
Dental plaque. Dental plaque is a biofilm or mass of bacteria that grows on surfaces within the mouth. It is a sticky colorless deposit at first, but when it forms tartar, it is often brown or pale yellow. It is commonly found between the teeth, on the front of teeth, behind teeth, on chewing surfaces, along the gumline, or below the gumline cervical margins.