By determining the period that the element is in. For example, Calcium is in period 2 therefore its valence electron is located on energy level 2.
Answer:
A mole ratio is a conversion factor that relates the amounts in moles of any two substances in a chemical reaction
Explanation:
Answer: The density of the material is 2.66 g/mL and it is likely this is made of Aluminum
Explanation:
The first step to know the material of the chunk of metal is to calculate its density. The general formula for density is P (density) = . Moreover, in this case, it is known the mass is 37.28 g, but the volume is not directly provided. However, we know the water in the graduated cylinder had a volume of 20.0 mL and this increased to 34.0 mL when the chunk of metal is added, this means the volume of the metal is 14 mL (34.0 mL - 20.0 mL = 14 mL). Now let's calculate the density:
This means the density of this metal is 2.66 g/mL, which can be rounded as 2. 7 g/mL, and according to the chart, this is the density of aluminum. Therefore, this material of this chunk is aluminum.
Answer:Elements of even atomic number and mass number are more stable than elements of odd atomic and mass numbers
Explanation: The fact that elements possessing even number of nucleons are more stable and abundant suggests that nucleons are paired in the nucleus. This even number of nucleons is commonly called a magic number because bit is associated with extra stability, abundance of elements and plenitude of isotopes of such elements.
These magic numbers are often numbers which are multiples of four.
From the molarity and volume of HClO4, we can determine how many moles of H+ we initially have:
0.18 M HClO4 * 0.100 L HClO4 = 0.018 moles H+
We can determine how many moles of OH- we have from the molarity and volume of LiOH:
0.27 M LiOH * 0.030 L LiOH = 0.0081 moles OH-
When the HClO4 and LiOH neutralize each other, the remaining will be
0.018 moles H+ - 0.0081 moles OH- = 0.0099 moles of excess H+
This means that the molarity [H+] will be
[H+] = 0.0099 moles H+ / (0.100 L + 0.030 L) = 0.07615 M
The pH of the solution will therefore be
pH = -log [H+] = -log 0.07615 = 1.12