Answer:
two
Explanation:
The number of significant figures needed in the answer is 2.
This is because when finding the products of two numbers, the result is as accurate as the least number of significant figures of the numbers being multiplied.
Here the numbers being multiplied are;
1.31m
6.5m
1.31m has 3 significant figures
6.5m has 2 significant figures.
So, the product will have 2 significant figures
Firstly we need to determine the partial pressure of O2:

We will now use the Henry's Law equation to determine the solubility of the gas:

Answer: Solubility is 2.7x10^-3 M
Mass = mr x moles
Mr of CuCl2 = ( 63.5) + ( 35.5 x 2) = 134.5
2.5 = 134.5 x moles
2.5 / 134.5 = moles
Moles = 0.019 (2DP)
0.25g of Al
Mr of Al = 27
0.25 = 27 x moles
0.25/ 27 = 0.0093 moles (2sf)
Hope this helps :)
Alkali metals are known for being some of the most reactive metals. This is due in part to their larger atomic radii and low ionization energies. They tend to donate their electrons in reactions and often have an oxidation state of +1. These metals are characterized as being extre
Answer:
There are 0,011 moles of hydrogen gas.
Explanation:
We use the ideal gas formula, with the constant R = 0.082 l atm / K mol. The STP conditions are : 1 atm pressure and 273 K temperature. Solve for the formula, n (number of moles):
PV=nRT ---> n= (PV)/(RT)
n= (1 atm x 0,25 L)/ (0,082 l atm/ K mol x 273 K)
<em>n= 0,011 mol</em>