Explanation:
The chemical formula magnesium sulfide written as MgS and NOT 
because charge on magnesium ion is +2 and charge on sulfide ion is -2.
Therefore, these charges will cancel out each other as we write the formula in simplest crisscross method.
Also, the numbers in a chemical formula display the total number of atoms attached with each other or central atom.
For example, in 
there are two chlorine atoms attached to one calcium atom.
Therefore, 
denotes one sulfur atom is attached to magnesium atom. Hence, we do not write the formula of magnesium sulfide as because this shows two magnesium atoms are attached to two sulfur atoms which is not true.
Answer:
11 molecules of CH4.
23 atoms of C is the leftover.
Explanation:
Hello!
In this case, for the formation of methane:
We can see there is an excess of carbon based on their stoichiometry, because the needed amount of hydrogen gas molecules would be:
Thus, the formed molecules of methane are computed below:
In such a way, the leftover of carbon atoms are:
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Answer:
weighing balance/analytical balance
Graduated cylinder/buret
Explanation:
The mass of the evaporating basin could be measured using a weighing balance or an analytical balance. Both are classified as weighing scales but the analytical balance can measure the mass of objects up to 4 decimal places, thus, providing better accuracy in measurement than ordinary weighing balance that can only measure up to 2 decimal places.
In order to measure 50 cm3 of the sea water, a graduated cylinder or a buret can be used. Both equipment can measure up to the same decimal places and, thus, have virtually the same accuracy.
Answer:
Option (2)
Explanation:
Since the amount of each sample is the same, we are looking for the metal with the greatest density, which is copper.
Answer:
9. 8.2x10¹⁴ Hz
Explanation:
Wavelength λ = 366 nm
Formula: Frequency = C / λ
To find the wavelength in m,
1 nm = 1.0x10⁻⁹ m
So, 366 nm = ?
= 3.66x10⁻⁷ m
Frequency = 3.0x10⁸m.s-1 / 3.66x10⁻⁷ m
= 8.2x10¹⁴ s-1
