Which of the following samples will have the lowest pressure if they are all at the same temperature and in identical containers (same volume)? a. 15 g Ne
b. 15 g
c. 15 g Kr
d. 15 g CO2
e. 15gF2
f. All of these samples will have the same pressure.

c. 15 g Kr

Explanation:

The amount of a gas (Moles) is directely proportional to its pressure. That means the higher amount of moles, the highest pressure and vice versa.

Using molar mass of the compounds (Ne=20.2g/mol, Ar = 39.9g/mol, Kr = 83.8g/mol, CO₂ = 44 g/mol and F₂ = 38.0g/mol), moles of 15.0g of each gas are:

Ne = 15g ₓ (1mol / 20.2g) = 0.74 moles of Ne

Ar = 15g ₓ (1mol / 39.9g) = 0.38 moles of Ar

Kr = 15g ₓ (1mol / 83.8g) = 0.18 moles of Kr

CO₂ = 15g ₓ (1mol / 44g) = 0.34 moles of CO₂

F₂ = 15g ₓ (1mol / 38g) = 0.39 moles of F₂

(x-2) ( x+2) ( 2x + 5)

Step-by-step explanation:

We will factor the given expression by grouping

The expression is 2x³ + 5x² - 8x - 20

= ( 2x³ + 5x² ) - ( 8x + 20 )

= x² (2x + 5) - 4(2x + 5)  [ distributive property ]

= (a² -4) ( 2x + 5)

= (x-2) (x+2) (2x+5)  [since a² - b² = ( a+b ) (a-b) ]

Then the factored form of the expression will be (x-2) ( x+2) ( 2x + 5)