w/w percentage <span>
= mass of the pure compound /
total mass of the sample x 100%
70% HNO₃
contains by mass means every 100 g of sample has 70 g of HNO₃.</span><span>
The mass of solution = 103.8 g
Hence the mass of HNO₃ = 103.8 g x 70%</span><span>
= 103.8 g x (70 / 100)
<span>
= 72.66 g = 72.7 g.</span></span>
Answer:
<em>3.27·10²³ atoms of O</em>
Explanation:
To figure out the amount of oxygen atoms in this sample, we must first evaluate the sample.
The chemical formula for sodium sulfate is <em>Na₂SO₄, </em>and its molar mass is approximately 142.05
.
We will use stoichiometry to convert from our mass of <em>Na₂SO₄ </em>to moles of <em>Na₂SO₄</em>, and then from moles of <em>Na₂SO₄ </em>to moles of <em>O </em>using the mole ratio; then finally, we will convert from moles of <em>O </em>to atoms of <em>O </em>using Avogadro's constant.
19.3g <em>Na₂SO₄</em> · 
· 
·
After doing the math for this dimensional analysis, you should get a quantity of approximately <em>3.27·10²³ atoms of O</em>.
Answer:
Polymerization.
Explanation:
Polymerization can be defined as a type of chemical reaction in which molecules that are relatively small in size chemically combine to form a huge chain of molecules.
Simply stated, polymerization refers to a chemical reaction where two or more smaller molecules react to produce larger molecules of the same network or repetitive structural units.
In polymerization, the relatively small molecules are generally referred to as monomers while the larger molecules they produce are known as polymers.
Polymerization is given by the chemical formula;
nA -----> A(n).
In this scenario, Luis uses a stencil to repeat the same design on each wall to form one long grapevine with a bunch of grapes every foot along its length.
Hence, the type of chemical reaction this best model is polymerization because it involved repeating the same design (monomers) to form a long grapevine with a bunch of grapes (polymers).
Answer:
Mass = 14.64 g
Explanation:
Given data:
Volume of solution = 1.25 L
Molarity of Solution = 0.15 M
Mass of CaF₂ = ?
Solution:
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
We will calculate the number of moles of CaF₂ and then determine the mass by using number of moles.
0.15 M = number of moles of solute / 1.25 L
number of moles of solute = 0.15 M × 1.25 L
number of moles of solute = 0.1875 mol/L × L
number of moles of solute = 0.1875 mol
Mass in gram:
Mass = number of moles × molar mass
Mass = 0.1875 mol ×78.07 g/mol
Mass = 14.64 g
Molarity is defined as number of moles of solute in 1 L of solution.
Here, 0.1025 g of Cu is reacted with 35 mL of HNO_{3} to produced Cu^{2+} ions.
The balanced reaction will be as follows:
Cu+3HNO_{3}\rightarrow Cu(NO_{3})_{2}+NO_{2}+H_{2}O
From the above reaction, 1 mole of Cu produces 1 mole of Cu^{2+}, convert the mass of Cu into number of moles as follows:
n=\frac{m}{M}
molar mass of Cu is 63.55 g/mol thus,
n=\frac{0.1025 g}{63.55 g/mol}=0.0016 mol
Now, total molarity of solution, after addition of water is 200 mL or 0.2 L can be calculated as follows:
M=\frac{n}{V}=\frac{0.0016 mol}{0.2 L}=0.008 mol/L=0.008 M
Thus, molarity of Cu^{2+} is 0.008 M.
