Answer:
The reaction is endothermic
Part A: Yes because there is an immediate reaction of bubbling vigorously.
Part B: It releases energy because when the compounds are added together they are immediately releasing it by bubbling and turning cold.
Part C: Yes because the liquids inside when combined give off coldness that makes the liquid temperature decrease to use this chemical reaction could definitely be used to keep something cold
Explanation:
Answer : The volume of 4.9 M 
stock solution used to prepare the solution is, 12.24 ml
Solution : Given,
Molarity of aqueous solution = 1.20 M = 1.20 mole/L
Volume of aqueous solution = 50.0 ml = 0.05 L
(1 L = 1000 ml)
Molarity of stock solution = 4.9 M = 4.9 mole/L
Formula used :
where,
= Molarity of aqueous solution
= Molarity of stock solution
= Volume of aqueous solution
= Volume of stock solution
Now put all the given values in this formula, we get the volume of stock solution.
By rearranging the term, we get
Therefore, the volume of 4.9 M stock solution used to prepare the solution is, 12.24 ml
Answer:
The most recent ice age ended about 10,000 years ago
Explanation:
The last ice age began 110,000 years ago and ended 10,000 years ago, leading to the temperature of the Earth, expansions of glaciers and polar ice caps were made.
Answer:
First write the balanced equation for the reaction of HCl with Zn (NOTE: the previous answer did NOT do this and thus obtained an incorrect answer)
Zn + 2HCl ==> ZnCl2 + H2(g)
moles of H2 desired: PV = nRT
n = PV/RT = (1 atm)(10L)/(0.0821 Latm/Kmol)(298K)
n = 0.409 mole H2 desired
moles Zn needed:
0.409 moles H2 x 1 mole Zn/2 moles HCl = 0.204 moles Zn needed
mass Zn needed = 0.204 moles Zn x 65.4 g/mol = 13.4 g Zn needed (to 3 sig. figs.)
Explanation:people always get this wrong but i got you
Observation, hypothesis, experiment is the correct answer
