Answer:
Are sessile, have tentacles, mouths open downwards
Explanation:
Medusae may have many tentacles with which they catch their prey. Sometimes, people bathing in the ocean are touched by a medusa. Their tentacles are long and thin and covered in venomous stinging cells (known as nematocysts). They inject poison which immobilizes small fish. People who are stung should seek medical attention. There have been some deaths after severe medusa stings.
Answer:
4.49dm3
Explanation:
2NH4Cl + Ca(OH)2 —> CaCl2 + 2NH3 + 2H2O
First, we need to convert 10g of ammonium chloride to mole. This is illustrated below:
Molar Mass of NH4Cl = 14 + (4x1) + 35.5 = 53.5g/mol
Mass of NH4Cl = 10g
Number of mole = Mass /Molar Mass
Number of mole of NH4Cl = 10/53.5 = 0.187mol
From the equation,
2moles of NH4Cl produced 2 moles of NH3.
Therefore, 0.187mol of NH4Cl will also produce 0.187mol of NH3
Now we can obtain the volume of NH3 produced by doing the following:
1mole of any gas occupy 24dm3
Therefore, 0.187mol of NH3 will occupy = 0.187 x 24 = 4.49dm3
Answer: -
100 mm Hg
Explanation: -
P 1 =400 mm Hg
T 1 = 63.5 C + 273 = 336.5 K
T 2 = 34.9 C + 273 = 307.9 K
ΔHvap = 39.3 KJ/mol = 39.3 x 10³ J mol⁻¹
R = 8.314 J ⁻¹K mol⁻¹
Now using the Clausius Clapeyron equation
ln (P1 / P2) = ΔHvap / R x (1 / T2 - 1 / T1)
Plugging in the values
ln (400 mm/ P₂) = (39.3 x 10³ J mol⁻¹ / 8.314 J ⁻¹K mol⁻¹) x (
- 
= 1.38
P₂ = 100 mm Hg
False .... A neutral atom needs the same number of protons and electrons
