Answer:
Value of expressions in scientific notation = 15.86 x 10⁻¹⁰
Explanation:
Given expressions:
2.600 x 10⁻⁵ x 6.100 x 10⁻⁵
Find:
Value of expressions in scientific notation
Computation:
2.600 x 10⁻⁵ x 6.100 x 10⁻⁵
2.600 x 6.100 x 10⁻⁵x 10⁻⁵
15.86 x 10⁻⁵ x 10⁻⁵
We know that;
qᵃ x qᵇ = q⁽ᵃ⁺ᵇ⁾
So,
15.86 x 10⁽⁻⁵⁻⁵⁾
15.86 x 10⁽⁻¹⁰⁾
Value of expressions in scientific notation = 15.86 x 10⁻¹⁰
Answer:
0.9 moles of Hg contain 5.418×10²³ atoms
Explanation:
As we know, Avogadro's number (NA) is the amount of particles that are contained in 1 mol → 6.02×10²³
Let's make a rule of three for this:
6.02×10²³ atoms are contained in 1 mol of Hg
5.418×10²³ atoms would be contained in (5.418×10²³ . 1) / NA = 0.9 moles
Explanation:
Ions are the species that contain a charge either positive or negative charge.
When a neutral atom loses an electron then it acquires a positive charge. Whereas if a neutral atom gains an electron then it acquires a negative charge.
For example, 
means there is +1 charge on sodium.
But if a compound does not contain any charge then it means the compound is neutral.
For example, in the compound 
there is no charge so, this compound is neutral.
Hence, we can conclude that no ions are present in a sample of .
Answer:
(b) gas and dust
Explanation:
"The interstellar medium is the stuff between the stars. Made up mostly of hydrogen and helium gas – plus trace amounts of ices, silicate grains, and all the other elements – it contains all the material needed to make stars and planets. It is shaped by stellar winds, dying stars, galactic magnetic fields, and supernova explosions."
"The interstellar medium is filled primarily with hydrogen gas. A relatively significant amount of helium has also been detected, along with smaller percentages of such substances as calcium, sodium, water, ammonia, and formaldehyde . Sizable quantities of dust particles of uncertain composition are present as well."
