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2 years ago

What is the molality of a solution that contains 109 grams of NaOH dissolved in 4.55kg of water? The molar mass of NaOH is 40.00

1 answer:

8 0

$C_{m}=\frac{n}{V}=\frac{m_{s}}{MV}\\\\
d=\frac{m}{V} \ \ \ \Rightarrow \ \ \ V=\frac{m}{d}=\frac{4550g}{1\frac{g}{cm^{3}}}=4550cm^{3}=4,55L\\\\
C_{m}=\frac{109g}{40\frac{g}{mol}*4,55L}\approx0,6M$

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Can the crabs see the plankton they eat near the ocean floor?

cricket20 [7]

Answer:

Explanation:

The crabs cannot see the plankton they eat near the ocean floor. For the crabs to see the plankton, some color of visible light would need to reach the plankton so that it can be reflected into the crabs' eyes.

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2 years ago

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What istope of an atom if it has 29 protons and 36 neutrons?<br>

Lunna [17]

Answer:

Copper Atoms

Explanation:

All copper atoms have atomic number 29: all their nuclei contain 29 protons. But they also contain uncharged particles called neutrons. In natural copper, the atoms are of two kinds. One has 29 protons and 34 neutrons in the nucleus; the other has 29 protons and 36 neutrons

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3 years ago

In an endothermic reaction what is true of the enthalpy

charle [14.2K]

Answer is: a) is has increased.

There are two types of reaction:

1) endothermic reaction (chemical reaction that absorbs more energy than it releases).

For example, the breakdown of ozone is an endothermic process. Ozone has lower energy than molecular oxygen (O₂) and oxygen atom, so ozone need energy to break bond between oxygen atoms.

2) exothermic reaction (chemical reaction that releases more energy than it absorbs).

For example, ΔH(reaction) = -225 kJ/mol; this is exothermic reaction.

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3 years ago

Name each of the following species for the following acid-base reactions. (The equilibrium lies to the right in each case, i.e.,

DaniilM [7]

Answer: a) $H_3O^++CH_3O^-\rightleftharpoons CH_3OH+H_2O$

acid : hydronium ion

base : methoxide ion

conjugate acid : methanol

conjugate base: water

b) $CH_3CH_2O^-+HCl\rightleftharpoons CH_3CH_2OH+Cl^-$

acid : hydrogen chloride

base : ethoxide ion

conjugate acid : ethanol

conjugate base: chloride ion

c) $NH_2^-+CH_3OH\rightleftharpoons NH_3+CH_3O^-$

acid : methanol

base : amide ion

conjugate acid : ammonia

conjugate base: methoxide ion

Explanation:

According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.

The species accepting a proton is considered as a base and after accepting a proton, it forms a conjugate acid.

The species losing a proton is considered as an acid and after loosing a proton, it forms a conjugate base

For the given chemical equation:

a) $H_3O^++CH_3O^-\rightleftharpoons CH_3OH+H_2O$

acid : hydronium ion

base : methoxide ion

conjugate acid : methanol

conjugate base: water

b) $CH_3CH_2O^-+HCl\rightleftharpoons CH_3CH_2OH+Cl^-$

acid : hydrogen chloride

base : ethoxide ion

conjugate acid : ethanol

conjugate base: chloride ion

c) $NH_2^-+CH_3OH\rightleftharpoons NH_3+CH_3O^-$

acid : methanol

base : amide ion

conjugate acid : ammonia

conjugate base: methoxide ion

3 0

2 years ago

Calculate how many grams of the first reactant are necessary to completely react with 17.3 g of the second reactant. the reactio

soldier1979 [14.2K]

Taking into account the reaction stoichiometry, 16.611 grams of Na₂CO₃ are necessary to completely react with 17.3 g of CuCl₂.

<h3>Reaction stoichiometry</h3>

In first place, the balanced reaction is:

Na₂CO₃ + CuCl₂ → CuCO₃ + 2 NaCl

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

Na₂CO₃: 1 mole
CuCl₂: 1 mole
CuCO₃: 1 mole
NaCl: 2 moles

The molar mass of the compounds is:

Na₂CO₃: 129 g/mole
CuCl₂: 134.45 g/mole
CuCO₃: 123.55 g/mole
NaCl: 58.45 g/mole

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

Na₂CO₃: 1 mole ×129 g/mole= 129 grams
CuCl₂: 1 mole ×134.45 g/mole= 134.45 grams
CuCO₃: 1 mole ×123.55 g/mole= 123.55 grams
NaCl: 2 mole ×58.45 g/mole=116.9 grams

<h3>Mass of CuCl₂ required</h3>

The following rule of three can be applied: If by reaction stoichiometry 134.35 grams of CuCl₂ react with 129 grams of Na₂CO₃, 17.3 grams of CuCl₂ react with how much mass of Na₂CO₃?

mass of Na₂CO₃= (17.3 grams of CuCl₂× 129 grams of Na₂CO₃)÷ 134.35 grams of CuCl₂

<u><em>mass of Na₂CO₃= 16.611 grams</em></u>

Finally, 16.611 grams of Na₂CO₃ is required.

Learn more about the reaction stoichiometry:

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brainly.com/question/24653699

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6 0

10 months ago