Answer:1. 5
Explanation: the element is boron and the atomic number is 5
<span> 52.0ml of 0.35M CH3COOH : 0.052 L(0.35M) = .0182 mol of CH3COOH.
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<span>31.0ml of 0.40M NaOH : .031 L(0.40M) = .0124 mol of NaOH.
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<span>After the reaction, .0124 Mol CH3COO- is generated and .058 mol CH3COOH is left un-reacted. The concentration would be 12.4/V and 5.8/V, respectively. Therefore:
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<span>pH = -log([H+]) = -log(Ka*[CH3COOH]/[CH3COO-]) </span>
<span>= -log(1.8x10^-5*5.8/12.4) = 5.07</span>
Hey there!
Just say what color you think the mixture would look like if those elements were combined. Personally I don't know because I don't have context, but if it comes to it just pick a color :)
Good luck, have a good night.
<span>8.278 g/mL
The definition of density is mass per volume. So what you need to do is divide the known mass by the known volume. So
1.663 g / 0.2009 mL = 8.27775 g/mL
But you also have to keep track of significant figures. Since both 1.663 and 0.2009 have 4 significant figures each, you need to round the result to 4 significant figures. So
8.27775 g/mL = 8.278 g/mL</span>
