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3 years ago

A chemist reacts 30.0 mL of 5.6 M HCl with an excess of Mg(OH)2 How many grams of magnesium will be produced

Chemistry

1 answer:

Mkey [24]3 years ago

3 0

Answer:

2.042 g

Explanation:

The reaction that takes place is:

2HCl + Mg(OH)₂ → Mg²⁺ + 2Cl⁻ + 2H₂O

First we calculate how many HCl moles were added, using the given volume and concentration:

30 mL ⇒ 30 / 1000 = 0.030 L

5.6 M * 0.030 L = 0.168 mol HCl

Then we convert HCl moles into Mg²⁺ moles, using the stoichiometric coefficients:

0.168 mol HCl * $\frac{1molMg^{+2}}{2molHCl}$ = 0.084 mol Mg⁺²

Finally we convert Mg moles into grams, using its molar mass:

0.084 mol Mg⁺² * 24.305 g/mol = 2.042 g

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How many moles of Fe are in 235.45g of Fe

Elena-2011 [213]

We are given with an element Iron, Fe, with a mass of 235.45 g. We are tasked to solve for its corresponding molar mass in mol. We need to find first the molecular weight of Iron, that is
Fe= 55.845 g/mol
With 235.45 g sample, its corresponding mol is

mol Fe= 235.45 g x 1 mol/55.845 = 4.22 mol Fe
Therefore, molar mass of Iron is 4.22 mol

3 0

3 years ago

A solution at 25 ∘C has pOH = 10.53. Which of the following statements is or are true? The solution is acidic. The pH of the sol

Lady bird [3.3K]

Answer:

The true statements are:

The solution is acidic

The pH of the solution is 14.00 - 10.53.

$10^{-10.53}=[OH^-]$

Explanation:

The pH of the solution is defined as negative logarithm of hydrogen ion concentration present in the solution .

$pH=-\log[H^+]$

The pH value more 7 means that hydrogen ion concentration is less ,alkaline will be the solution.
The pH value less 7 means that hydrogen ion concentration is more ,acidic will be the solution.
The pH value equal to 7 indicates that the solution is neutral.

The pOH of the solution is defined as negative logarithm of hydroxide ion concentration present in the solution .

$pOH=-\log[OH^-]$

The pOH of the solution = 10.53

$10.53=-\log[OH^-]$

$10^{-10.53}=[OH^-]$

The pH of the solution = ?

$pH+pOH=14$

$pH=14-pOH=14-10.53=3.47$

Here, the pH of the solution is less than 7 which means that solution acidic.

8 0

2 years ago

Which is a property of potassium (K)? O A. It is dull and brittle. O B. It is not reactive. O C. It is white and hard. O D. It i

atroni [7]

Answer:

D. It is extremely reactive.

Explanation:

Potassium has atomic number of 19 and belongs to the group 1 elements.

A. It is dull and brittle

This is not true as potassium is a metal with a silver lustre.

B. It is not reactive

This is false. Because it is a group 1 element, it would readily lose it's electron to achieve octet configuration making it a reactive metal.

C. It is white and hard.

Potassium is a white metal, however it is not hard. Rather it is soft.

D. It is extremely reactive.

This is correct. Because it is a group 1 element, it would readily lose it's electron to achieve octet configuration making it a reactive metal.

5 0

3 years ago

The aromatic hydrocarbon cymene (C10H14) is found in nearly 100 spices and fragrances, including coriander, anise, and thyme. Th

andrezito [222]

Answer : The thermal energy produced during the complete combustion of one mole of cymene is -7193 kJ/mole

Explanation :

First we have to calculate the heat released by the combustion.

$q=c\times \Delta T$

where,

q = heat released = ?

$c$ = specific heat of calorimeter = $3.640kJ/^oC$

$\Delta T$ = change in temperature = $19.35^oC$

Now put all the given values in the above formula, we get:

$q=3.640kJ/^oC\times (19.35)^oC$

$q=70.43kJ$

Thus, the heat released by the combustion = 70.43 kJ

Now we have to calculate the molar enthalpy combustion.

$\Delta H=-\frac{q}{n}$

where,

$\Delta H$ = molar enthalpy combustion = ?

q = heat released = 70.43 kJ

n = number of moles cymene = $\frac{\text{Mass of cymene}}{\text{Molar mass of cymene}}=\frac{1.608g}{164.22g/mol}=0.009792mole$

$\Delta H=-\frac{70.43kJ}{0.009792mole}=-7193kJ/mole$

Therefore, the thermal energy produced during the complete combustion of one mole of cymene is -7193 kJ/mole

4 0

3 years ago

Aqueous sulfuric acid will react with solid sodium hydroxide to produce aqueous sodium sulfate and liquid water . Suppose 2.9 g

garri49 [273]

Answer:

1.07 g of water.

Explanation:

A reaction between an acid and a base makes water and a salt as product.

Our reaction is:

H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O

Reactants are the acid and the base. Which is the limiting?

2.9 g . 1mol /98 g = 0.0296 moles of acid

3.53 g . 1mol / 40 g = 0.088 moles of base

2 moles of base react to 1 mol of acid

0.088 moles may react to (0.088 . 1)/2 = 0.044 moles of acid

And we only have 0.0296, sulfuric acid is the limiting

Ratio is 1:2. 1 mol of acid can produce 2 moles of water.

Our 0.0296 moles may produce (0.0296 . 2) /1 = 0.0592 moles of water.

We convert moles to mass:

0.0592 mol . 18g /mol = 1.07 g

6 0

3 years ago