Answer:
The nichrome wire is dirty.
The solution is contaminated.
Explanation:
If the nichrome wire is dirty, it may contain sodium contaminants which may be responsible for the yellow flame. The nichrome wire is first inserted into the flame without the sample to check for impurities.
The test solution may also have been contaminated. This leads to the appearance of a colour different from the expected colour of the test cation in the solution.
Answer:- oxygen.
Explanations:- The electronic configuration is given and we are asked to figure out the electrically neutral atom that will have the electron configuration, .
The sum of electrons for this electron configuration is 8. If we look at the periodic table then 8 is the atomic number of oxygen.
So, the electrically neutral atom for the given electron configuration is oxygen.
Answer:
Ionic compounds generally form between elements that are metals and elements that are nonmetals. For example, the metal calcium (Ca) and the nonmetal chlorine (Cl) form the ionic compound calcium chloride (CaCl2). In this compound, there are two negative chloride ions for each positive calcium ion
<h3><u>Answer;</u></h3>
<u>= 5 M or 5 moles/liter</u>
<h3><u>Explanation;</u></h3>
At point E, 90 g of substances X are dissolved in 100 g of the solvent.
100g of the solvent is equal to 100 ml
Molarity is the number of moles of a substance in one liter of a solvent.
90 g of X are in 100 ml
But; the RFM of X = 180 g/l
Therefore; the moles of X in 90 g = 90/180
= 0.5 moles
Therefore;
0.5 moles of X are contained in 100 ml of the solvent;
Thus, molarity = 0.5 × 1000/100
=<u> 5 M or 5 moles/liter</u>