Answer:
The electronic configuration of the element with Atomic number 19 is 2,8,8,1. The element is potassium. It is an alkali metal with one valence electron.
Answer:
The mass of 0.280 mole sample of sodium hydroxide NaOH is 11.2 grams.
Explanation:
To know the mass in grams of 0.280 moles of sample of sodium hydroxide NaOH, you must know the molar mass of the compound, that is, the mass of one mole of a substance, which can be an element or a compound.
So you know:
- Na: 23 g/mole
- O: 16 g/mole
- H: 1 g/mole
So, the molar mass of NaOH is:
NaOH= 23 g/mole + 16 g/mole+ 1 g/mole= 40 g/mole
Then the following rule of three can be applied: if in 1 mole of sodium hydroxide there are 40 grams, in 0.280 moles how much mass is there?

mass= 11.2 grams
<u><em>The mass of 0.280 mole sample of sodium hydroxide NaOH is 11.2 grams.</em></u>
Answer:
5.5 L
Explanation:
First we <u>convert 10 g of propane gas</u> (C₃H₈) to moles, using its <em>molar mass</em>:
- 10 g ÷ 44 g/mol = 0.23 mol
Then we <u>use the PV=nRT formula</u>, where:
- P = 1 atm & T = 293 K (This are normal conditions of T and P)
- R = 0.082 atm·L·mol⁻¹·K⁻¹
1 atm * V = 0.23 mol * 0.082 atm·L·mol⁻¹·K⁻¹ * 293 K
Magnesium and I think its MG12 for the other part
Density = mass/volume = 2000/4000 = 0.5 grams/cm3. Hope this hopes!