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3 years ago

A chemist measures the energy change ?H during the following reaction:

Chemistry

1 answer:

Leno4ka [110]3 years ago

5 0

Answer:

(A) endothermic

(A) Yes, absorbed

Explanation:

Let's consider the following thermochemical equation.

2 Fe₂O₃(s) ⇒ 4 FeO(s) + O₂(g) ΔH = 560 kJ

Since ΔH > 0, the reaction is endothermic.

We can establish the following relations:

560 kJ are absorbed when 2 moles of Fe₂O₃ react.
The molar mass of Fe₂O₃ is 160 g/mol.

Suppose 66.6 g of Fe₂O₃ react. The heat absorbed is:

$66.6g.\frac{1mol}{160g} .\frac{560kJ}{2mol} =117kJ$

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What is the mass, in grams, of one mole of any substance known as?

lbvjy [14]

It is known as its molar mass.

5 0

2 years ago

Read 2 more answers

Sodium hydrogen carbonate NaHCO3, also known as sodium bicarbonate or "baking soda", can be used to relieve acid indigestion. Ac

olga2289 [7]

Answer:

1.4952 grams of sodium bicarbonate she would need to ingest to neutralize this much HCl.

Explanation:

$Moles (n)=Molarity(M)\times Volume (L)$

Moles of hydrochloric acid = n

Volume of hydrochloric acid solution = 200.0 mL = 0.200 L

Molarity of the hydrochloric acid = 0.089 M

$n=0.089 M\times 0.200 L=0.0178 mol$ of HCL

$HCl(aq)+NaHCO_3(aq)\rightarrow NaCl(aq)+H_2O(l)+CO_2(g)$

According to reaction, 1 mole of HCl is neutralized by 1 mole of sodium bicarbonate.

Then 0.0178 moles of HCl wil be neutralized by :

$\frac{1}{1}\times 0.0178 mol=0.0178 mol$ of sodium bicarbonate

Mass of 0.0178 moles of sodium bicarbonate:

0.0178 mol × 72 g/mol = 1.4952 g

1.4952 grams of sodium bicarbonate she would need to ingest to neutralize this much HCl.

8 0

2 years ago

Human blood typically contains 1.04 kg/L of platelets. A 1.89 pints of blood would contain what mass (in grams) of platelets

Fynjy0 [20]

Answer:

The correct answer is 930 grams platelets.

Explanation:

The volume of blood given is 1.89 pints. Total number of gallons in 1.89 pints is,

= 1.89/8 = 0.236 gallon

1 gallon comprise = 3.785 L

So, 0.236 gallon comprise = 0.236 * 3.785 L = 0.89 L

As mentioned that 1 Liter of blood comprise 1.04 kilograms of platelets. Therefore, 0.89 L of blood will contain = 1.04 * 0.89 = 0.93 Kg platelets

1 Kg contain 1000 grams. So, number of platelets in grams will be,

= 1000 * 0.93 = 930 grams platelets.

3 0

2 years ago

Indicate whether each of the following statements is correct or incorrect.1)Every Bronsted-Lowry acid is also a Lewis acid2)Ever

Hunter-Best [27]

Answer:

1) correct

2) incorrect

3) correct

4)incorrect

Explanation:

1) A Lewis acid is a substance that accepts a nonbonding pair of electrons.

A Bronsted-Lowry acid is a substance that donates a proton H⁺

Since the donation of a proton involves the acceptance of a pair of electrons, every Bronsted-Lowry acid is also a Lewis acid.

2)A Lewis acid not necessarily needs to have a proton to be donated.

3) Conjugated acids of weak bases are strong acids and conjugated acids of strong bases are weak acids.

4)K⁺ comes from a strong base, therefore is does not have an acidic behaviour.

4 0

2 years ago

If you increase the solute amount but keep the solution volume the same what

solmaris [256]

Answer: Molarity increases

Explanation:

Molarity, also known as concentration in moles/dm3 or g/dm3, is calculated by dividing the amount of solute dissolved by the volume of solvent. So, Molarity (c) = amount of solute (n) / volume (v)

i.e c = n/v

Hence, molarity is directly proportional to the amount of solute dissolved, and inversely proportional to the volume of solvent.

Thus, at same volume, any increase in solute amount increases molarity while a decrease will also decreases molarity.

4 0

2 years ago