We may use the molecular formula of the compound to determine the number of oxygen atoms in one formula unit. The formula unit is:
Mg(NO₃)₂
Here, we can see that there are two nitrate ions in each mole, and each mole of nitrate ion contains three oxygen atoms. Thus, there are 6 oxygen atoms in each formula unit of magnesium nitrate.
Answer:
A. 30cm³
Explanation:
Based on the chemical reaction:
CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂
<em>1 mol of calcium carbonate reacts with 2 moles of HCl to produce 1 mol of CO₂</em>
<em />
To solve this question we must convert the mass of each reactant to moles. With the moles we can find limiting reactant and the moles of CO₂ produced. Using PV = nRT we can find the volume of the gas:
<em>Moles CaCO₃ -Molar mass: 100.09g/mol-</em>
1.00g * (1mol / 100.09g) = 9.991x10⁻³ moles
<em>Moles HCl:</em>
50cm³ = 0.0500dm³ * (0.05 mol / dm³) = 2.5x10⁻³ moles
For a complete reaction of 2.5x10⁻³ moles HCl there are necessaries:
2.5x10⁻³ moles HCl * (1mol CaCO₃ / 2mol HCl) = 1.25x10⁻³ moles CaCO₃. As there are 9.991x10⁻³ moles, HCl is limiting reactant.
The moles produced of CO₂ are:
2.5x10⁻³ moles HCl * (1mol CO₂ / 2mol HCl) = 1.25x10⁻³ moles CO₂
Using PV = nRT
<em>Where P is pressure = 1atm assuming STP</em>
<em>V volume in L</em>
<em>n moles = 1.25x10⁻³ moles CO₂</em>
<em>R gas constant = 0.082atmL/molK</em>
<em>T = 273.15K at STP</em>
<em />
V = nRT / P
1.25x10⁻³ moles * 0.082atmL/molK*273.15K / 1atm = V
0.028L = V
28cm³ = V
As 28cm³ ≈ 30cm³
Right option is:
<h3>A. 30cm³</h3>
Because chloride is more reactive than hydrogen.
Answer:
0.30 M
Explanation:
Using integrated rate law for first order kinetics as:
![[A_t]=[A_0]e^{-kt}](https://tex.z-dn.net/?f=%5BA_t%5D%3D%5BA_0%5De%5E%7B-kt%7D)
Where,
![[A_t]](https://tex.z-dn.net/?f=%5BA_t%5D)
is the concentration at time t = ?
![[A_0]](https://tex.z-dn.net/?f=%5BA_0%5D)
is the initial concentration = 1.36 M
k is the rate constant = 0.208 s⁻¹
t = 7.30 seconds
So,
![[A_t]=1.36\times e^{-0.208\times 7.30}\ M=0.30\ M](https://tex.z-dn.net/?f=%5BA_t%5D%3D1.36%5Ctimes%20e%5E%7B-0.208%5Ctimes%207.30%7D%5C%20M%3D0.30%5C%20M)
