After two half-lives or 60 years, 7.5 g of the element will be left.
<u>Explanation:</u>
<u>Half-life:</u>
- In simple words, Half-life can be defined as the amount of time needed for a quantity to fall to half its value as contained at the beginning of the time period.
- In this problem the half-life of the element is thirty years, then after thirty years half of the sample would have decayed and half would be left as it is.
- After thirty years (The first half-life ) 30 /2 = 15 g declines and 15 g remains disappeared.
- And after another sixty years (The two half-lives) 15 /2 = 7.5 g declines and 7.5 g remains disappeared.
- After two half-lives or 60 years, 7.5 g of the element will be left.
Type of chocolate bar, size of it, surface it is placed on, etc
Controlled variables are anything that stay the same for both trials
Answer:
Acid deposition-usually referred to simply as acid rain-actually includes two forms of pollution, wet and dry. ... In the wet type of acid deposition, these compounds combine with water vapor in the atmosphere to form highly corrosive sulfuric and nitric acids.
Explanation:
The accumulation of acids or acidic compounds on the surface of the Earth, in lakes or streams, or on objects or vegetation near the Earth's surface, as a result of their separation from the atmosphere. Acid deposition can harm the environment in a variety of ways, as by causing the acidification of lakes and streams, the leaching of minerals and other nutrients from soil, and the inhibition of nitrogen fixation and photosynthesis in plants.♦ The accumulation of acids that fall to the Earth dissolved in water is known as wet deposition. Wet deposition includes all forms of acid precipitation such as acid rain, snow, and fog.♦ The accumulation of acidic particles that settle out of the atmosphere or of acidic gases that are absorbed by plant tissues or other surfaces is known as dry deposition.
