It tells you how many protons it has and because the number of protons =electrons it tells you also the number of electrons.
A should be the products and D should be the reactants. So D should be the answer.
Let us assume that there is a 100g sample of Opal. The masses of each element will be:
29.2g Si
33.3g O
37.5g H2O
Now we divide each constituent's mass by its Mr to get the moles present
Si: (29.2 / 28) = 1.04
O: (33.3 / 16) = 2.08
H2O: (37.5 / 18) = 2.08
Now we divide by the smallest number and obtain:
Si: 1
O: 2
H2O: 2
Thus, the empirical formula of Opal is:
SiO2 . 2H2O
Answer:
5.71 g
Explanation:
Step 1: Write the balanced equation
2 K + Cl₂ ⇒ 2 KCl
Step 2: Calculate the moles corresponding to 12.0 g of KCl
The molar mass of KCl is 74.55 g/mol.
12.0 g × 1 mol/74.55 g = 0.161 mol
Step 3: Calculate the moles of Cl₂ needed to produce 0.161 moles of KCl
The molar ratio of Cl₂ to KCl is 1:2. The moles of Cl₂ needed are 1/2 × 0.161 mol = 0.0805 mol
Step 4: Calculate the mass corresponding to 0.0805 moles of Cl₂
The molar mass of Cl₂ is 70.91 g/mol.
0.0805 mol × 70.91 g/mol = 5.71 g
