Answer:
final pressure ( P2) = 467.37 mm Hg
Explanation:
ideal gas:
∴ P1 = 570 mm Hg * ( atm / 760 mm Hg ) = 0.75 atm
∴ T1 = 25 ° C = 298 K
∴ V1 = 1.250 L
∴ R = 0.082 atm L / K mol
⇒ n = P1*V1 / R*T1
⇒ n = (( 0.75 ) * ( 1.25 )) / (( 0.082 ) * ( 298 ))
⇒ n = 0.038 mol gas
∴ T2 = 175 °C ( 448 K )
∴ V2 = 2.270 L
⇒ P2 = nRT2 / V2
⇒ P2 = (( 0.038 ) * ( 0.082 ) * ( 448 )) / 2.270
⇒ P2 = 0.615 atm * ( 760 mm Hg / atm ) = 467.37 mm Hg
Answer:
12.99
Explanation:
<em>A chemist dissolves 716. mg of pure potassium hydroxide in enough water to make up 130. mL of solution. Calculate the pH of the solution. (The temperature of the solution is 25 °C.) Be sure your answer has the correct number of significant digits.</em>
Step 1: Given data
- Mass of KOH: 716. mg (0.716 g)
- Volume of the solution: 130. mL (0.130 L)
Step 2: Calculate the moles corresponding to 0.716 g of KOH
The molar mass of KOH is 56.11 g/mol.
0.716 g × 1 mol/56.11 g = 0.0128 mol
Step 3: Calculate the molar concentration of KOH
[KOH] = 0.0128 mol/0.130 L = 0.0985 M
Step 4: Write the ionization reaction of KOH
KOH(aq) ⇒ K⁺(aq) + OH⁻(aq)
The molar ratio of KOH to OH⁻is 1:1. Then, [OH⁻] = 0.0985 M
Step 5: Calculate the pOH
We will use the following expression.
pOH = -log [OH⁻] = -log 0.0985 = 1.01
Step 6: Calculate the pH
We will use the following expression.
pH + pOH = 14
pH = 14 - pOH = 14 -1.01 = 12.99
Answer:
Explanation:
no se hombre necisito pontos
Answer:
Parenchyma is the most simple and specialized tissue which is concerned mainly with the vegetative activities of the plant. The cells are isodiametric with well-developed intercellular spaces, vacuolated cytoplasm and cellulosic cell wall.
Collenchyma is the tissue of the primary body. The cells of the tissue contain protoplasm and are living without intercellular spaces. The cell wall articulate at the corners and are made up of cellulose, hemicellulose, and pectin.
Sclerenchyma is the thick-walled cell tissue. In the beginning, the cell is living and have protoplasm, but due to deposition of impermeable secondary board lignin, they become dead thick and hard.
