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3 years ago

A covalent chemical bonds in which_____.

1 answer:

6 0

The answer is C because a covalent bond has atoms that don’t have a strong electronegativity so neither one can pull electron(s) away from each other, they only can share it

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A student dissolves 15.0 g of ammonium chloride(NH4Cl) in 250. 0 g of water in a well-insulated open cup. She then observes the

iren2701 [21]

Answer:

1) Endothermic.

2) $Q_{rxn}=4435.04J$

3) $\Delta _rH=15.8kJ/mol$

Explanation:

Hello there!

1) In this case, for these calorimetry problems, we can realize that since the temperature decreases the reaction is endothermic because it is absorbing heat from the solution, that is why the temperature goes from 22.00 °C to 16.0°C.

2) Now, for the total heat released by the reaction, we first need to assume that all of it is released by the solution since it is possible to assume that the calorimeter is perfectly isolated. In such a way, it is also valid to assume that the specific heat of the solution is 4.184 J/(g°C) as it is mostly water, therefore, the heat released by the reaction is:

$Q_{rxn}=-(15.0g+250.0g)*4.184\frac{J}{g\°C}(16.0-20.0)\°C\\\\ Q_{rxn}=4435.04J$

3) Finally, since the enthalpy of reaction is calculated by dividing the heat released by the reaction over the moles of the solute, in this case NH4Cl, we proceed as follows:

$\Delta _rH=\frac{ Q_{rxn}}{n}\\\\\Delta _rH= \frac{ 4435.04J}{15.0g*\frac{1mol}{53.49g} } *\frac{1kJ}{1000J} \\\\\Delta _rH=15.8kJ/mol$

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4 0

3 years ago

What does the MC1R gene code for

zlopas [31]

The MC1R gene provides instructions for making a protein called the melanocortin 1 receptor. This receptor plays an important role in normal pigmentation. The receptor is primarily located on the surface of melanocytes, which are specialized cells that produce a pigment called melanin.

5 0

3 years ago

Read 2 more answers

Chlorine gas can be prepared in the laboratory by the reaction of hydrochloric acid with manganese(IV) oxide. 4 HCl ( aq ) + MnO

Leno4ka [110]

Answer:

1. HCl is the limiting reactant.

2. The theoretical yield of Cl2 is 23.197g

3. The Actual yield 19.787g

Explanation:

4HCl + MnO2 —> MnCl2 + 2H2O + Cl2

First let us calculate the number of mole of HCl and MnO2.

Molar Mass of HCl = 1 + 35.5 = 36.5g/mol

Mass of HCl = 47.7g

Number of mole = Mass /Molar Mass

Number of mole of HCl = 47.7/36.5 = 1.31mole

Molar Mass of MnO2 = 35 + (2x16) = 35 + 32 = 67g/mol

Mass of MnO2 = 40.5g

Number of mole = Mass /Molar Mass

Number of mole of MnO2 = 40.5/67 = 0.60mole

From equation,

4moles of HCl required 1mole of MnO2. Now let us consider the following:

4moles HCl require 1mole MnO2. Therefore 0.31mol of HCl will require = 0.31/4 = 0.0775mole of MnO2. This amount is little compared to the amount of MnO2 ( i.e 0.60mol) calculated. Therefore, HCl is the limiting reactant.

2. 4HCl + MnO2 —> MnCl2 + 2H2O + Cl2

Molar Mass of HCl = 36.5g/mol

Mass of HCl from the balanced equation = 4 x 36.5 = 146g

Molar Mass of Cl2 = 2 x 35.5 = 71g/mol

From the equation,

146g of HCl produced 71g of Cl2.

Therefore, 47.7g of HCl will produce = (47.7x 71)/146 = 23.197g of Cl2.

The theoretical yield of Cl2 is 23.197g

3. %yield = 85.3%

Theoretical yield = 23.197g

Actual yield =?

%yield = Actual yield /Theoretical yield

Actual yield = %yield x theoretical yield

Actual yield = 85.3% x 23.197g = (85.3/100) x 23.197 = 19.787g

5 0

3 years ago

When does a spring tide take place? At the beginning of spring Only during the spring season Only after spring is over At any ti

Naddika [18.5K]

Answer:

At any time.

Explanation:

Because it occurs in a full and a new moon.

HOPE THIS HELPS!!

8 0

4 years ago

If a mineral breaks into cubes when struck with a rock hammer whats being measured

emmainna [20.7K]

When struck, the mineral is tested for lattice type. Depending on how it shatters, scientists can determine how the mineral forms on the atomic level by noting the molecular weaknesses of the system. These weaknesses are the points at which the mineral breaks along.

Depending on the type of hammer, they could also be testing the tensile strength and, even possibly, the hardness, depending on the angle of the blow. How hard the rock can be hit without breaking is the TS, and whether or not the mineral is scratched by the hammer is the hardness.

4 0

4 years ago