invisable
you probably dont want to put that...
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.
Answer:
–500KJ
Explanation:
Data obtained from the question include the following:
Heat of reactant (Hr) = 800KJ
Heat of product (Hp) = 300KJ
Enthalphy change (ΔH) =..?
The enthalphy change is simply defined as the difference between the heat of product and the heat of reactant i.e
Enthalphy change = Heat of product – Heat of reactant
ΔH = Hp – Hr
With the above formula, we can easily calculate the enthalphy change as follow
ΔH = Hp – Hr
ΔH = 300 – 800
ΔH = –500KJ.
Therefore, the overall energy change for the reaction between hydrogen and oxygen shown in the diagram above is –500KJ
Answer:
answer is 76
Explanation:
pls mark me brainliest right
Answer:
Explanation:
Given that,
The dimensions of the board is 5.54 cm x 10.6 cm X 199 cm.
The mass of the board is 28.6 kg.
Since, 1 kg = 1000 grams
28.6 kg = 28.6 × 1000 g = 28600 grams
Density = mass/volume
So,
So, the density of a board is 
.
