<u>U</u> <u>VORBELLO</u> <u>FRANÇAIS</u><u>?</u><u>?</u><u>?</u>
Answer:
A beaker
Step-by-step explanation:
Specifically, I would use a 250 mL graduated beaker.
A beaker is appropriate to measure 100 mL of stock solution, because it's easy to pour into itscwide mouth from a large stock bottle.
You don't need precisely 100 mL solution.
If the beaker is graduated, you can easily measure 100 mL of the stock solution.
Even if it isn't graduated, 100 mL is just under half the volume of the beaker, and that should be good enough for your purposes (you will be using more precise measuring tools during the experiment).
<h3>Answer:</h3>
Strontium (Sr)
<h3>Explanation:</h3>
The condition given in statement is the presence of two valence electron. Hence, first we found the electronic configuration of given atoms as follow;
Rubidium [Kr] 5s¹
Strontium [Kr] 5s²
Zirconium [Kr] 4d² 5s²
Silver [Kr] 4d¹⁰ 5s¹
From above configurations it is cleared that only Strontium and Zirconium has two electrons in its valence shell.
We also know that s-block elements are more reactive than transition elements due to less shielding effect in transition elements hence, making it difficult for transition metals to loose electrons as compared to s-block elements. Therefore, we can conclude that Strontium present in s-block with two valence electrons is the correct answer.
Molar mass of Calcium ( Ca ) = 40.078 g/mol
Number of moles in 9.8 grams :
1 mole Ca -----------> 40.078 g
mole Ca -------------> 9.8 g
moles Ca = 9.8 / 40.078
moles Ca = 0.2445 moles
number of molecules:
1 mole ----------------> 6.02x10²³ molecules
0.2445 moles --------> ?
= 0.2445 * 6.02x10²³
= 1.47x10²³ molecules
hope this helps!.
Mass= number of moles multiply Mass of one mole
= 24.3 multiplied by 4
= 96.2
