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2 years ago

What is the mass of a 2.5 mole sample of MgO2

Chemistry

1 answer:

MrRa [10]2 years ago

6 0

Mass = no. of moles x molecular weight
m = n x Mr
m = 2.5 mol x (24 + [16 x 2])
m = 140g

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What family contains the most reactive nonmetals: halogen or alkali?

mart [117]

Halogen are the most reactive due to their electronic configuration

5 0

3 years ago

A 50.0-mL volume of 0.15 M HBr is titrated with 0.25 M KOH. Calculate the pH after the addition of 13.0 mL of KOH. Express your

Mazyrski [523]

Answer:

pH= 1.17

Explanation:

The neutralization reaction between HBr (acid) and KOH (base) is given by the following equation:

HBr(aq) + KOH(aq) → KBr(aq) + H₂O(l)

According to this equation, 1 mol of HBr reacts with 1 mol of KOH. Then, the moles can be expressed as the product between the molarity of the acid/base solution (M) and the volume in liters (V). So, we calculate the moles of acid and base:

Acid:

M(HBr) = 0.15 M = 0.15 mol/L

V(HBr) = 50.0 mL x 1 L/1000 mL = 0.05 L

moles of HBr = M(HBr) x V(HBr) = 0.15 mol/L x 0.05 L = 7.5 x 10⁻³ moles HBr

Base:

M(KOH) = 0.25 M = 0.25 mol/L

V(HBr) = 13.0 mL x 1 L/1000 mL = 0.013 L

moles of HBr = M(HBr) x V(HBr) = 0.25 mol/L x 0.013 L = 3.25 x 10⁻³ moles KOH

Now, we have: 7.5 x 10⁻³ moles HBr > 3.25 x 10⁻³ moles KOH

HBr is a strong acid and KOH is a strong base, so they are completely dissociated in water: the acid produces H⁺ ions and the base produces OH⁻ ions. So, the difference between the moles of HBr and the moles of KOH is equal to the moles of remaining H⁺ ions after neutralization:

moles of H⁺ = 7.5 x 10⁻³ moles HBr - 3.25 x 10⁻³ moles KOH = 4.25 x 10⁻³ moles H⁺

From the definition of pH:

pH = -log [H⁺]

The concentration of H⁺ ions is calculated from the moles of H⁺ divided into the total volume:

total volume = V(HBr) + V(KOH) = 0.05 L + 0.013 L = 0.063 L

[H⁺] = (moles of H⁺)/(total volume) = 4.25 x 10⁻³ moles/0.063 L = 0.067 M

Finally, we calculate the pH after neutralization:

pH = -log [H⁺] = -log (0.067) = 1.17

3 0

3 years ago

In the following net ionic equation, identify each reactant as either a Bronsted-Lowry acid or a Bronsted-Lowry base. HCN(aq) H2

vfiekz [6]

Answer:

Explanation:

The definition of acids and bases by Arrhenius Theory was modified and extended by Bronsted-Lowry.

Bronsted-Lowry defined acid as a molecule or ion which donates a proton while a base is a molecule or ions that accepts the proton. This definition can be extended to include acid -base titrations in non-aqueous solutions.

In this theory, the reaction of an acid with a base constitutes a transfer of a proton from the acid to the base.

From the given information:

$\mathsf{HCN _{(aq)} + H_2O_{(l)} \to CN^{-}_{(aq)} + H_3O_{(aq)}}$

From above:

We will see that HCN releases an H⁺ ion, thus it is a Bronsted-Lowry acid

$H_2O$ accepts the H⁺ ion ,thus it is a Bronsted-Lowry base.

The formula of the reactant that acts as a proton donor is HCN

The formula of the reactant that acts as a proton acceptor is H2O

8 0

2 years ago

What does C represent

zimovet [89]

Answer: the distance of energy from point d to e

8 0

2 years ago

Read 2 more answers

Calculate the specific heat of the substance if 373 J is required to raise the temperature of a 312 gram sample by 25°C?

I am Lyosha [343]

Explanation:

Q = 373J

∆∅ = 25°C

m = 312g

c = x

Q = mc∆∅

373 = 312(x)(25)

373 = 7800x

x = 373/7800

x = 0.0478J/(g°C)

4 0

3 years ago