Answer:
nitrogen
Explanation:
The stoichiometry of the reaction says that 
and 
react 3:1 to form 2 moles of 
, so, if you have 3,5 moles of H, which is equal to 1,75 moles of , and 5 moles of N, which are equal to 2,5 moles of 
. only
=0.583 moles of , will react, leaving <em>1.917 moles of </em> <em>unreacted</em>, and forming 0.583*2=1.166 moles of
The elements within a group in the table have similar properties. ... In general, how can the periodic trends displayed by elements be explained? What is the underlying cause of periodic trends? Trends in atomic size, ionization energy, ionic size, and electronegativity can be explained by variations in atomic structure.
Answer:
4 g after 58.2 years
0.0156 After 291 years
Explanation:
Given data:
Half-life of strontium-90 = 29.1 years
Initially present: 16g
mass present after 58.2 years =?
Mass present after 291 years =?
Solution:
Formula:
how much mass remains =1/ 2n (original mass) ……… (1)
Where “n” is the number of half lives
to find n
For 58.2 years
n = 58.2 years /29.1 years
n= 2
or 291 years
n = 291 years /29.1 years
n= 10
Put values in equation (1)
Mass after 58.2 years
mass remains =1/ 22 (16g)
mass remains =1/ 4 (16g)
mass remains = 4g
Mass after 58.2 years
mass remains =1/ 210 (16g)
mass remains =1/ 1024 (16g)
mass remains = 0.0156g
Answer: A. Endothermic
Explanation:
In an endothermic reaction, heat is sucked in from the surrounding area by the reactants so that they may use it to react and form new products. This will therefore reduce the temperature in the said surrounding by the amount that the reaction needed.
This is what ice does when it melts. It sucks in the heat surrounding the area and then melts but leaves the area colder. For instance, putting ice in water ensures that the ice melts but because it sucked in the heat from the water to do so, the water gets colder as a result.
