3 years ago

What is the mass number of 207Pb ? A: 289 B: 207 C: 125 D: 82

Chemistry

1 answer:

Sergio [31]3 years ago

3 0

207 is the mass number. 82 would be the atomic number

You might be interested in

An atom has eight protons and nine neutrons. draw the atomic structure of the atom

Cloud [144]

Draw eight circles and nine more in a big circle = this represents your nucleus
draw eight electrons (since electrons = protons in neutral elements) outside of it (2 in one ring, then 6 in a second ring)

7 0

2 years ago

Amplitude measures the light's

charle [14.2K]

Answer:

d.) intensity

Explanation:

8 0

3 years ago

Read 2 more answers

An acid with molar mass 84.48 g/mol is titrated with 0.650 M KOH. What volume of KOH solution is needed to titrate 1.70 grams of

RSB [31]

Answer:

$V=0.0310L=3.10mL$

Explanation:

Hello.

In this case, since the acid is monoprotic and the KOH has one hydroxyl ion only, we can see that at the equivalence point the moles of both of them are the same:

$n_{acid}=n_{KOH}$

Thus, since we are given 1.70 g of the acid, we compute the moles of acid that were titrated:

$n_{acid}=1.70g*\frac{1mol}{84.48g}=0.0201mol$

Which equal the moles of KOH. In such a way, since the molarity is defined as moles over liters (M=n/V), the liters are moles over molarity (V=n/M), thus, the resulting volume is:

$V=\frac{0.0201mol}{0.650mol/L}\\\\V=0.0310L=3.10mL$