<span>The student should
follow following steps to make 1 L of </span>2.0 M CaCl₂.<span>
<span>
1. First he should
calculate the number of moles of 2.0 M CaCl</span></span>₂ in 1 L solution.<span>
</span>Molarity of the solution = 2.0 M<span>
Volume of solution which should be prepared = 1 L
Molarity =
number of moles / volume of the solution
Hence, number of moles in 1 L = 2 mol
2. Find
out the mass of dry CaCl</span>₂ in 2 moles.<span>
moles =
mass / molar mass
Moles of CaCl₂ =
2 mol</span><span>
Molar mass of CaCl₂ = </span><span>110.98 g/mol
Hence, mass of CaCl</span>₂ = 2 mol x <span>110.98 g/mol
= 221.96
g
3. Weigh the mass
accurately
4. Then take a cleaned and dry1 L volumetric flask and place a funnel top of it. Then carefully add the salt into the volumetric flask and
finally wash the funnel and watch glass
with de-ionized water. That water also should be added into the volumetric
flask.
5. Then add some
de-ionized water into
the volumetric flask and swirl well until all salt are
dissolved.
<span>6. Then top up to
mark of the volumetric flask carefully.
</span></span>
7. As the final step prepared solution should be labelled.
20 grams is probably the mass
Answer : For the experiment to study the diffusion across the semi permeable membrane, following are the safety steps that will help to handle chemicals safety;
- Use droppers to transfer small amounts of chemicals into another glassware, it will prevent the unnecessary spillage of the chemical.
- Use tongs to move hot objects as they may cause severe burns.
- Check the test tubes for chips prior to using them otherwise it may leak the chemical inside it
- Washing your hands after you finishing the lab experiment, this will ensure that food is not contaminated while consuming, with the chemicals that were stuck on the hands.
Answer: I believe it's 8
Explanation: The oxygen atom has therefore 8 neutrons, 8 protons and 8 electrons.
It’s a synthesis reaction, which is when 2 or more substances react to form a single product.
I hope this helps
