They are in free fall. In a vacuum, gravity causes all objects to fall at the same rate, and since they all are falling together. The astronauts and other objects appear to float when compared with the spacecraft.
Answer: Anyway, the basic reason why the planets revolve around, or orbit, the Sun, is that the gravity of the Sun keeps them in their orbits. ... If the Sun weren't there, the Earth would travel in a straight line. But the gravity of the Sun alters its course, causing it to travel around the Sun, in a shape very near to a circle
Answer: 2755.2 g of 
will be produced from 24.6 mol of haematite.
Explanation:
The balanced chemical equation is:
According to stoichiometry :
1 mole of 
produce = 2 moles of
Thus 24.6 moles of will produce=
of
Mass of 
Thus 2755.2 g of will be produced from 24.6 mol of haematite.
Answer:
Explanation:
pH is derived from the concentration of hydronium ions in a solution. Hydrocyanic acid is HCN.
First, we shall figure out the moles of HCN:
If HCN was a strong acid:
HCN has a 1:1 ratio of H+ ions, the moles of H+ is also the same.
To find the molarity, we now divide by Liters. This gets us:
Finally, we plug it into the definition of pH:
![pH = -log[H^{+} ]](https://tex.z-dn.net/?f=pH%20%3D%20-log%5BH%5E%7B%2B%7D%20%5D)
However, since HCN is a weak acid, it only partially dissociates. The 
of HCN is 
.
![K_a = \frac{[H^+][A^-]}{[HA]}](https://tex.z-dn.net/?f=K_a%20%3D%20%5Cfrac%7B%5BH%5E%2B%5D%5BA%5E-%5D%7D%7B%5BHA%5D%7D)
We can use an ice table to determine that when x = H+,
![[H^+] = 8.83*10^{-6}](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%20%3D%208.83%2A10%5E%7B-6%7D)
<u>Given:</u>
Concentration of Na₂S = 0.765 M
Volume of Na₂S solution = 25.0 ml = 0.025 L
Final total volume = 225 ml = 0.225 L
<u>To determine:</u>
The concentration of Na+ ions
<u>Explanation:</u>
# moles of Na₂S = 0.765 * 0.025 = 0.0191 moles
Based on the atomic stoichiometry of Na₂S-
# moles of Na⁺ ions = 2*0.0191 = 0.0382 moles
conc of Na⁺ ions = 0.0382 moles/ 0.225 L = 0.169 M
Ans: [Na⁺] = 0.169 M
