Answer:
9.69g
Explanation:
To find the needed outcome, we first need to determine the number of moles of N2 present in 7.744L of the gas.
1 mole of gas takes up 22.4L at STP.
Thus, X moles of nitrogen gas (N2) will fill 7.744L, meaning
X moles of N2 = 7.744/22.4 = 0.346 moles
Next, we will convert 0.346 moles of N2 to grams to achieve the result sought. The calculation goes as follows:
Molar Mass of N2 = 2x14 = 28g/mol
Number of moles N2 = 0.346 moles
Find the mass of N2 =?
Mass = number of moles × molar mass
Mass of N2 = 0.346 × 28
Mass of N2 = 9.69g
Hence, 7.744L of N2 consists of 9.69g of N2
Answer:
The adjustable legs along with the sand table.
Note: The question is incomplete. The full question is presented below.
Using Models to Address Questions Regarding Systems
Armando’s class was examining images of rivers shaped by flowing water. Most rivers appeared wide and shallow, except for one, which was narrow and deep. The students theorized that this river's narrowness and depth are due to:
- the steepness of the hill from which the water descends, or
- the diminutive size of the sand grains the water flows through.
To explore the answer to the question of why this river is so narrow and deep, Armando created the model outlined below.
Explanation:
The model constructed by Armando will facilitate addressing the question due to specific features:
1. Adjustable leg - as one theory proposed by the class suggests that the steep hill affecting the water's path could be the reason for the river's dimensions, the adjustable legs are designed to be raised or lowered to alter the slope, allowing testing of this theory.
2. Sand table - this acts as the streambed. By modifying the size of the sand grains, students can examine the second hypothesis that smaller sand grains contribute to the river's narrowness and depth.
The outcomes of their experimentation will lead them to a conclusion.
N₀ signifies the quantity of C-14 atoms per kg of carbon in the original sample at time = 0 seconds, when the carbon composition matched that in today’s atmosphere. As time progresses to ts, the number of C-14 atoms per kg declines to N, due to radioactive decay. λ indicates the decay constant.
Hence, we have N = N₀e - λt, which is the equation for radioactive decay. Rearranging gives us N₀/N = e λt, or In(N₀/N) = - λt, which becomes equation 1.
The sample contains mc kg of carbon, leading to an activity measured as A/mc decay per kg. The variable r represents the initial mass of C-14 in the sample at t=0 relative to the total mass of carbon which is calculated as [(total number of C-14 atoms at t = 0) × ma] / total mass of carbon. Thus, N₀ equates to r/ma, which becomes equation 2.
The activity of the radioactive element is directly related to the atom count at the moment. The activity equation A = dN/dt = λ(N) indicates that: A = λ₁(N × mc). Rearranging provides N = A / (λmc), represented in equation 3.
By integrating equations 2 and 3, we can solve for t yielding
t = (1/λ) In(rλmc/m₀A).
Answer:
K2X
Explanation:
The term valency refers to an element's capacity to combine with other elements. This property determines how an element is represented in a chemical compound's formula.
For magnesium and element X, represented as MgX, magnesium typically has a valency of +2 in its compounds. The absence of the +2 in the formula implies that element X must possess a -2 valency, resulting in a cancellation of the valencies.
Furthermore, potassium is classified as an alkaline metal in group 1 of the periodic table, leading to an expected valency of +1.
When forming a compound with element X, a valency exchange occurs. Since X has a -2 valency, the resulting formula of the compound formed by the exchange will be K2X.
