Answer:
- There will be 1.23 moles of helium in the balloon at STP
Explanation:
1) <u>Initial conditions of the helium gas</u>:
- V = 20.0 liter
- p = 1.50 atm
- T = 25.0 °C = 25.0 + 273.15 K = 298.15 K
2) <u>Ideal gas equation</u>:
- pV = n RT
- p, V, and T are given above
- R is the Universal constant = 0.0821 atm-liter / ( K - mol)
- n is the unknown number of moles
3) <u>Solve for n</u>:
- n = 1.50 atm × 20.0 liter / (0.0821 atm-liter /k -mol ×298.15K)
4) <u>At STP:</u>
- STP stands for standard pressure and temperature.
- The amount (number of moles) of the gas will not change because the change of pressure and temperature, so the number of moles reamain the same: 1.23 mol.
Answer:
pure water, pH = 7.0 (Neutral)
lake water, pH = 6.5 (Acidic)
baking soda solution, pH = 9 (Alkaline)
soapy water, pH = 12 (Alkaline)
Explanation:
The degree of acidicity or alkalinity of a solution can be determined on a pH meter. A pH below 7 is acidic; a pH of 7 is neutral; a pH value of above 7 is alkaline.
A temperature change in a reaction indicates a chemical change
False. The element abundant in our body is oxygen and on earth, it is still oxygen. The body is more than 50% water. A water molecule is 11% hydrogen and the rest is oxygen. That is why you can expect oxygen to be abundant in the body. Same is true with the earth. Majority of the oxygen is from the bodies of water the earth is rich of.
A battery is a device that is able to store electrical<span> energy in the form of chemical energy, and convert that energy into </span>electricity
