H^+ = acid
OH^- = alkaline
Acids have a pH of below 7. The lower the number, the strongest the acid.
<span>For that we need to know something about the chemistry aluminum sulfide and aluminum hydroxide. Aluminum sulfide will react with water to make insoluble aluminum hydroxide and hydrogen sulfide gas. Therefore, we need a balanced chemical equation.
Al2S3(s) + 6HOH --> 2Al(OH)3(s) + 3H2S(g)
17.7g ........................ ???g
17.7g Al2S3 x (1 mol Al2S3 / 150.3 g Al2S3) x (2 mol Al(OH)3 / 1 mol Al2S3) x (78.0g Al(OH)3 / 1 mol Al(OH)3) = 18.4 g Al(OH)3 ...... to three significant digits.</span>
Solution;
The gas is at STP;
Where; T = 273 K , P = 1 atm
We know that 1 mole of a gas at STP occupies a volume of 22.4 liters .
V1/n1 = V2/n2
n2 = (V2/V1) n1
n2 = (2 l/22.4 l)(1 mole)
n2 = 0.0893 moles
But 1 mole of a compound has 6.022 × 10^23 molecules
Thus, number of molecules = 0.0893 moles × 6.022 ×10^23 molecules
= 5.378 × 10^22 molecules.
Answer & Explanation:
In physics, a contact force is a force that acts at the point of contact between two objects, in contrast to body forces. Contact forces are described by Newton's laws of motion, as with all other forces in dynamics. Contact force is the force in which an object comes in contact with another object. Contact forces are also direct forces. Contact forces are ubiquitous and are responsible for most visible interactions between macroscopic collections of matter. Pushing a car up a hill or kicking a ball or pushing a desk across a room are some of the everyday examples where contact forces are at work. In the first case the force is continuously applied by the person on the car, while in the second case the force is delivered in a short impulse.
