Take a random sample of nuts from the jar. Let's take two handfuls, after shaking the jar and mixing the nuts thoroughly. Separate the nuts into almonds and cashews. Count each pile, then do the following calculation (these numbers are random, for example only).

Count Percentage %

Almonds 38 (38)/(87)x100

Cashews 49 49/87x100

87 87/87 = 100%

Ratio of Almonds to Cashews: 38/49

3 0

2 years ago

How can you tell that a gas is a halogen? ___?

OLEGan [10]

If it is located at the second to last row of the periodic table (the halogen family), has seven electrons on it's outer shell, and has an oxidation number of -1, it is a halogen.
Hope this helps : D

8 0

3 years ago

Typical "hard" water contains about 2.0 x 10–3 mol of Ca2+ per liter. Calculate the maximum concentration of fluoride ion that c

malfutka [58]

Answer:

$[F^-]_{max}=4x10{-3}\frac{molF^-}{L}$

Explanation:

Hello,

In this case, for the described situation, we infer that calcium reacts with fluoride ions to yield insoluble calcium fluoride as shown below:

$Ca^{+2}(aq)+2F^-(aq)\rightleftharpoons CaF_2(s)$

Which is typically an equilibrium reaction, since calcium fluoride is able to come back to the ions. In such a way, since the maximum amount is computed via stoichiometry, we can see a 1:2 mole ratio between the ions, therefore, the required maximum amount of fluoride ions in the "hard" water (assuming no other ions) turns out:

$[F^-]_{max}=2.0x10^{-3}\frac{molCa^{2+}}{L}*\frac{2molF^-}{1molCa^{2+}} \\$

$[F^-]_{max}=4x10{-3}\frac{molF^-}{L}$

Best regards.

8 0

3 years ago