1. Write out the formula
Pb(NO3)2 (aq) + 2HCl (aq) ----> PbCl2 + 2HNO3
2. Use solubility guidelines (gotta memorize 'em) for the products to see if a solid forms
Nitrates are always soluble so 2HNO3 (aq)
Chlorides (Cl) are always soluble except for when you mix them with copper, lead, mercury, or silver.
Since you mixed it with lead (Pb) it is solid and forms a precipitate. PbCl2 (s)
Moles of Zn: 26 / 65 = 0.4
Moles of S: 12.8 / 32 = 0.4
Molar ratio of Zn : S = 1 : 1
Empircal formula: ZnS
The answer is C
Answer:
B. Conclusions are based on observations
Explanation:
Complete question is;
A drop of water has a volume of approximately 7 × 10⁻² ml. How many water molecules does it contain? The density of water is 1.0 g/cm³.
This question will require us to first find the number of moles and then use avogadro's number to get the number of water molecules.
<em><u>Number of water molecules = 2.34 × 10²¹ molecules</u></em>
We are given;
Volume of water; V = 7 × 10⁻² ml
Density of water; ρ = 1 g/cm³ = 1 g/ml
Formula for mass is; m = ρV
m = 1 × 7 × 10⁻²
m = 7 × 10⁻² g
from online calculation, molar mass of water = 18.01 g/mol
Number of moles(n) = mass/molar mass
Thus;
n = (7 × 10⁻²)/18.01
n = 3.887 × 10⁻³ mol
from avogadro's number, we know that;
1 mol = 6.022 × 10²³ molecules
Thus,3.887 × 10⁻³ mol will give; 6.022 × 10²³ × 3.887 × 10⁻³ = 2.34 × 10²¹ molecules
Read more at; brainly.in/question/17990661
= 0.3571 L or 0.4 L