<u>Answer:</u>
• 7.64 g Bi = 2.20 x 10²² atoms
• 35.8 g P = 6.95 x 10²³ atoms
<u>Explanation:</u>
First calculate the number of moles in each sample:
no. of moles = mass ÷ molar mass (RMM)
• 7.64 g Bi = 7.64 ÷ 209
= 0.03656 mol
• 35.8 g P = 35.8 ÷ 31
= 1.155 mol
Then multiply the number of moles by Avogadro's constant (6.02x10²³):
• 0.03656 x 6.02x10²³ = 2.20 x 10²² atoms
• 1.155 x 6.02x10²³ = 6.95 x 10²³ atoms
Answer:
A) 60
Explanation:
Given data:
Distance traveled by car = 210 km
Time taken = 3.5 hour
Speed of car = ?
Solution:
Formula:
S = d/t
s = speed of car
d = distance
t = time
by putting values,
s = 210 km / 3.5 hour
s = 60 km/hour
A buffer is a solution that can resist pH change upon the addition of an acidic or basic components. It is able to neutralize small amounts of added acid or base, thus maintaining the pH of the solution relatively stable.
Answer:
C. 0.04 moles per cubic decimeter.
Explanation:
The molar mass of the Iodine is 253.809 grams per mole and a cubic decimeter equals 1000 cubic centimeters. The concentration of Iodine (
), measured in moles per cubic decimeter, can be determined by the following formula:
(1)
Where:
- Mass of iodine, measured in grams.
- Molar mass of iodine, measured in grams per mol.
- Volume of solution, measured in cubic decimeters.
If we know that
,
and
, then the concentration of iodine in a solution is:
![c = \frac{2.54\,g}{\left(253.809\,\frac{g}{mol} \right)\cdot (0.25\,dm^{3})}](https://tex.z-dn.net/?f=c%20%3D%20%5Cfrac%7B2.54%5C%2Cg%7D%7B%5Cleft%28253.809%5C%2C%5Cfrac%7Bg%7D%7Bmol%7D%20%5Cright%29%5Ccdot%20%280.25%5C%2Cdm%5E%7B3%7D%29%7D)
![c = 0.04\,\frac{mol}{dm^{3}}](https://tex.z-dn.net/?f=c%20%3D%200.04%5C%2C%5Cfrac%7Bmol%7D%7Bdm%5E%7B3%7D%7D)
Hence, the correct answer is C.
Metal - they are good conductors of electricity, malleable (easily shaped) and ductile (can be drawn into wires)