The acidity of a substance relates to the proportion of free hydrogen ions (H+) it contains. Acidity is measured on a logarithmic scale. Even a small decrease in pH of ocean water can cause a large increase in hydrogen ions and acidity. This increase can have grave effects on marine ecosystems. For the last 300 million years, the average pH of the oceans has been 8.2. Today, the average pH is 8.1. Using the hydrogen ion concentrations, what is the percent increase in acidity of the ocean in the past compared to today?

Brian's school locker has a three-digit combination lock that can be set using the numbers 5 to 9 (including 5 and 9), without repeating a number. the probability that the locker code begins with a prime number is %. the probability that the last digit of the locker code is an odd number is %.

If the distance between two points on the ground is 10 miles and the distance between the same two points on a map is 4 inches, what is the map scale expressed as a ratio?

What is the difference between the cultures of central asia and the caucasus region? the majority of people in central asia are muslim; the majority in the caucasus region are christian. the primary language in central asia is armenian; the primary language in the caucasus region is russian. central asia has been plagued by ethnic unrest; the caucasus region has had little ethnic conflict. the effects of soviet rule can still be seen in central asia; the caucasus region has developed its own identity since the fall of the ussr.