Answer:
2.5
Explanation:
The given costs for the purchase and delivery of the cupcakes are;
The cost of 10 cupcakes and the delivery fee = $30
The cost of 25 cupcakes and the delivery fee = $67.50
Let 'c' represent the fixed cost of delivery of the cup cakes, and let 'x' represent the cost of each cup cake, we have;
30 = 10·x + c...(1)
67.50 = 25·x + c...(2)
Subtracting equation (1) from equation (2) gives;
67.50 - 30 = 37.50 = 25·x - 10·x + c - c = 15·x
∴ x = 37.50/15 = 2.5
The cost of each cupcake, x = 2.5
(∴ The delivery fee = 30 - 10 × 2.5 = 5)
The cost of each cupcake is 2.5.
The element that’s more reactive then the others is Selenium
We can use the ideal gas law equation to find the pressure
PV = nRTwhere
P - pressure
V - volume - 2.6 x 10⁻³ m³
n - number of moles - 0.44 mol
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature - 25 °C + 273 = 298 K
substituting the values into the equation,
P x 2.6 x 10⁻³ m³ = 0.44 mol x 8.314 Jmol⁻¹K⁻¹ x 298 K
P = 419 281.41 Pa
101 325 Pa is equivalent to 1 atm
Therefore 419 281.41 Pa - 1/ 101 325 x 419 281.41 = 4.13 atm
Pressure is 4.13 atm
