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4 years ago

If 0.66 g magnesium reacts exactly with 0.43 g oxygen, what mass of magnesium oxide will be produced?

1 answer:

5 0

Balanced equation for the reaction is;
2Mg + O₂ --> 2MgO
stoichiometry of Mg to O₂ is 2:1
we need to first find the limiting reactant
number of Mg moles - 0.66 g / 23 g/mol = 0.029 mol
number of O₂ moles - 0.43 g / 32 g/mol = 0.013 mol
If Mg is the limiting reactant
2 mol of Mg reacts with 1 mol of O₂
then 0.029 mol of Mg reacts with - 0.029/2 = 0.0145 mol
but only 0.013 mol of O₂ is present
therefore O₂ is limiting reactant. amount of product formed depends on amount of limiting reactant present,
stoichiometry of O₂ to MgO is 1:2
when 0.013 mol of O₂ reacts - 0.026 mol of MgO is formed
mass of MgO produced is - 0.026 mol x 39 g/mol = 1.014 g
1.014 g of MgO formed

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Answer:

Number of moles (n)=

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3 years ago

A mixture of 0.10 mol of NO, 0.050 mol of H2, and 0.10 mol of H2O is placed in a 1.0- L vessel at 300 K . The following equilibr

umka2103 [35]

Answer:

The concentration of N2 at the equilibrium will be 0.019 M

Explanation:

Step 1: Data given

Number of moles of NO = 0.10 mol

Number of moles of H2 = 0.050 mol

Number of moles of H2O = 0.10 mol

Volume = 1.0 L

Temperature = 300K

At equilibrium [NO]=0.062M

Step 2: The balanced equation

2NO(g) + 2H2(g) → N2(g) + 2H2O(g)

Step 3: Calculate the initial concentration

Concentration = Moles / volume

[NO] = 0.10 mol / 1L = 0.10 M

[H2] = 0.050 mol / 1L = 0.050 M

[H2O] = 0.10 mol / 1L = 0.10 M

[N2] = 0 M

Step 4: Calculate the concentration at the equilibrium

[NO] at the equilibrium is 0.062 M

This means there reacted 0.038 mol (0.038M) of NO

For 2 moles NO we need 2 moles of H2 to produce 1 mol N2 and 2 moles of H2O

This means there will also react 0.038 mol of H2

The concentration at the equilibrium is 0.050 - 0.038 = 0.012 M

There will be porduced 0.038 moles of H2O, this means the final concentration pf H2O at the equilibrium is 0.100 + 0.038 = 0.138 M

There will be produced 0.038/2 = 0.019 moles of N2

The concentration of N2 at the equilibrium will be 0.019 M

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3 years ago

Why is ice in a glacer considered to be a mineral but water a glacier is not

-Dominant- [34]

If you have a book, read it!! I promise you, it tells you this answer!

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3 years ago

During an investigation, a student burns magnesium to form magnesium oxide. The starting mass of magnesium is measured as 21.3 g

enot [183]

Answer:

Percentage yield = 85.2%

Explanation:

Given data:

Mass of Mg = 21.3 g

Actual yield of MgO = 30.2 g

Percentage yield = ?

Solution:

Chemical equation:

2Mg + O₂ → 2MgO

Number of moles of Mg = mass/molar mass

Number of moles of Mg = 21.3 g / 24.3 g/mol

Number of moles of Mg = 0.88 mol

Now we will compare the moles of MgO with Mg.

Mg : MgO

2 : 2

0.88 : 0.88

Mass of MgO:

Mass of MgO= moles × molar mass

Mass of MgO= 0.88 mol × 40.3g/mol

Mass of MgO = 35.46 g

Actual yield of MgO = 30.2 g

Percentage yield:

Percentage yield = Actual yield/theoretical yield × 100

Percentage yield = 30.2 g/ 35.46 g × 100

Percentage yield = 85.2%

3 0

3 years ago

An electron in the hydrogen atom makes a transition from an energy state of principal quantum number ni to the n = 2 state. If t

topjm [15]

Answer:

$\boxed{3}$

Explanation:

The Rydberg equation gives the wavelength λ for the transitions:

$\dfrac{1}{\lambda} = R \left ( \dfrac{1}{n_{i}^{2}} - \dfrac{1}{n_{f}^{2}} \right )$

where

R= the Rydberg constant (1.0974 ×10⁷ m⁻¹) and

$\text{$n_{i}$ and $n_{f}$ are the numbers of the energy levels}$

Data:

$n_{f} = 2$

λ = 657 nm

Calculation:

$\begin{array}{rcl}\dfrac{1}{657 \times 10^{-9}} & = & 1.0974 \times 10^{7}\left ( \dfrac{1}{2^{2}} - \dfrac{1}{n_{f}^{2}} \right )\\\\1.522 \times 10^{6} &= &1.0974\times10^{7}\left(\dfrac{1}{4} - \dfrac{1}{n_{f}^{2}} \right )\\\\0.1387 & = &\dfrac{1}{4} - \dfrac{1}{n_{f}^{2}} \\\\-0.1113 & = & -\dfrac{1}{n_{f}^{2}} \\\\n_{f}^{2} & = & \dfrac{1}{0.1113}\\\\n_{f}^{2} & = & 8.98\\n_{f} & = & 2.997 \approx \mathbf{3}\\\end{array}\\\text{The value of $n_{i}$ is }\boxed{\mathbf{3}}$

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3 years ago