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.
Each element<span> can usually be classified as a metal or a non-metal based on their ... They are usually </span>dull<span>and therefore show no metallic </span>luster<span> and they do not reflect ... </span>Dull<span>, Brittle solids; Little or no metallic </span>luster<span>; </span>High<span> ionization energies; </span>High<span> ...</span>
ANSWER:
Potential energy due to the position of an object above Earth's surface is called gravitational potential energy.
EXPLANATION:
Gravitational energy is the potential energy compared with gravitational force, as work is needed to further things against Earth’s gravity. The potential energy due to high positions is called gravitational potential energy, and is evidenced by water in an elevated storage or kept behind a dam. If an article falls from one point to different point inside a gravitational field, the force of gravitation will do actual work on the object, and the gravitational potential energy will decrease by the same amount.
Answer:
D
Explanation:
On the left hand side there are a total of 4 hydrogen and 2 oxygen but on the right hand side there Is only 2 hydrogen and 1 oxygen
<u>Answer:</u> The mass of solid NaOH required is 80 g
<u>Explanation:</u>
Equivalent weight is calculated by dividing the molecular weight by n factor. The equation used is:

where,
n = acidity for bases = 1 (For NaOH)
Molar mass of NaOH = 40 g/mol
Putting values in above equation, we get:

Normality is defined as the umber of gram equivalents dissolved per liter of the solution.
Mathematically,

Or,
......(1)
We are given:
Given mass of NaOH = ?
Equivalent mass of NaOH = 40 g/eq
Volume of solution = 400 mL
Normality of solution = 5 eq/L
Putting values in equation 1, we get:

Hence, the mass of solid NaOH required is 80 g