Answer:
1. Data:
a) Half-life: 5730 years
b) Final radioactivity: 68%
2. Solution:
a) <u>Determine the number of half-lives undergone</u>
- Since, <em>the radioactivity has decreased to 68%, means that the carbon-14 contanined is has been reduced in </em> 32%: 100% - 68% = 32%.
- 32 = 2⁵, meaning that five half-lives have passed since the <em>plant material</em> that formed the<em> parchment fragment died</em>.
b) <u>Compute the time of five half-lives</u>:
- 5 × half-life time = 5 × 5730 years = 28,650 years.
c) <u>Round to the nearest hundred:</u>
- 28,650 years ≈ 28,700 years
And that is <em>the age of the parchment</em>.
Millimeters are an SI unit of length that =0.0001 m
Mass of water added:
0.997 x 1500
= 1495.5 grams
a) Volume = mass / density
Volume = 1495.5 / 0.917
Volume = 1630 cm³ = 1.63 L
b) The ice cannot be contained in the bottle as its volume exceeds that of the bottle.
Answer: the pH is 11.78
Explanation:Please see attachment for explanation
Answer:
See explanation
Explanation:
When a beaker of ethanoic acid is placed in the refrigerator, its temperature drops and the vessel feels cool.
Now, when we mix ethanoic acid and sodium carbonate, an endothermic reaction occurs, fizzing is observed as carbon dioxide is given off and heat is lost to the surroundings causing the reaction vessel to feel cool to touch.
The difference between putting ethanoic acid in the refrigerator and adding sodium carbonate to the solution is that, in the former, no new substance is formed. The substance remains ethanoic acid when retrieved from the refrigerator. In the later case, new substances are formed. The substance is no more ethanoic acid because a chemical reaction has taken place.
