<em>Hardness is a measure of how resistant solid matter is to various kinds of permanent shape change when a force is applied</em> <em>Macroscopic hardness is generally characterized by</em> <em>strong intermolecular bonds</em>, <em>but the behavior of solid materials under force is complex; therefore,</em> <em>there are different measurements of hardness</em>: <em>scratch hardness, indentation hardness, and rebound hardness. Hardness is dependent on ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity. Common examples of hard matter are ceramics, concrete, certain metals, and super hard materials, which can be contrasted with soft matter.</em>
The answer is Closed. Hope it helps
Answer:
After 48 hours amount left = 6.25 g
Explanation:
Given data:
Half life of potassium = 12 hours
Total mass = 100 g
Mass left after 48 hours = ?
Solution:
Number of half lives passed:
Number of half lives = Time elapsed / half life
Number of half lives = 48 hours/ 12 hours
Number of half lives = 4
At time zero = 100 g
At first half life = 100 g/ 2 = 50 g
At 2nd half life = 50 g/2 = 25 g
At 3rd half life = 25 g/2 = 12.5g
At 4th half life = 12.5 g/2 = 6.25 g
C...the key is that they are photosynthetic...so they produce oxygen (like plants)!
