Remember: energy is conserved in a chemical reaction (visualize the reaction and question whether heat lies on reactant side (left) or product side (right))
-exothermic- heat is released (heat is on the product side)
>forming an ionic lattice (SALT)- mixture of Na and Cl results in a more stable ionic lattice, causing this reaction to be exothermic
>burning wood
-endothermic- heat is absorbed (heat is on the reactant side)
> cooking an egg
Answer:
Considering the half-life of 10,000 years, after 20,000 years we will have a fourth of the remaining amount.
Explanation:
The half-time is the time a radioisotope takes to decay and lose half of its mass. Therefore, we can make the following scheme to know the amount remaining after a period of time:
Time_________________ Amount
t=0_____________________x
t=10,000 years____________x/2
t=20,000 years___________x/4
During the first 10,000 years the radioisotope lost half of its mass. After 10,000 years more (which means 2 half-lives), the remaining amount also lost half of its mass. Therefore, after 20,000 years, the we will have a fourth of the initial amount.
The percentage error is given by multiplying relative error by 100%.
Therefore, to get the percentage error we need relative error which is given by dividing the absolute error with the actual value.
Absolute error = 0.133
Percentage error = 0.133/5.586 × 100%
= 2.38%
The percentage error is therefore; 2.38%
Answer:
Wavelength (λ) – The distance of one complete cycle in the wave. The distance between two consecutive crests and /or troughs. S.I. Unit: metre (m).
In other words:
Wavelength is the distance from crest to crest (or trough to trough).
Answer:
<u>84.00 kPa = 630.084 torr</u>
Formula for kPa to torr: For an approximate result, multiply the pressure value by 7.501. <em><u>84* 7.501</u></em>
<u>84.00 kPa = 0.831683168 atm</u>
Formula for kPa to atm: for an approximate result, divide the pressure value by 101. <em><u>84/101</u></em>
