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3 years ago

Mucin, a component of saliva, functions to __________.

1 answer:

4 0

A critical function of mucin in saliva is to protect the mouth from drying out. Mucin also lubricates the tissues and teeth in the mouth and protects them against pathogens and toxins

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Using Avogadro's Number (6.02*10^23): Calculate the number of molecules in 3.00 moles H2S . Express your answer numerically in m

mars1129 [50]

Avagadro's number is just a measurement. One mole is 6.022 X 10^23 of anything - atoms, molecules, marbles... anything.
1) If one mole = 6.022 X 10^23, then 8.00mol of H2S is: 
(3.00mol H2S) (6.022 X 10^23 molecules H2S / 1 mol H2S) = 1.8060 X 10^24 molecules H2S. 
Rounded to 3 sig figs =1.81 X 10^24 molecules H2S
part2.
 This one uses moles in the stoichiometric sense as well as the measurement. One formula unit of MgCl2 contains 1 mole Mg and 2 moles Cl. 
First, figure out how many moles of formula units there are. 
(1.81 X 10^24 FU's) (1mol MgCl2 / 6.022 X 10^23 FU's) = 3.0056mol MgCl2.

Now, we know that there are 2 moles of Cl in every mole of MgCl2 (2 Cl atoms in every unit of MgCl2). From this we can determine how many moles of Cl atoms there are: 
(3.0056mol MgCl2) (2mol Cl atoms / 1mol MgCl2) = 6.0112mol Cl atoms. 
Now round to 3 sig figs = 10.0mol Cl atoms

3 0

3 years ago

Read 2 more answers

According to the following reaction, how many grams of water are produced in the complete reaction of 29.7 grams of ammonia? 4 N

Gnesinka [82]

Answer: The mass of water produced in the reaction is 47.25 grams.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

Given mass of ammonia = 29.7 g

Molar mass of ammonia = 17 g/mol

Putting values in equation 1, we get:

$\text{Moles of ammonia}=\frac{29.7g}{17g/mol}=1.75mol$

The given chemical reaction follows:

$4NH_3(g)+5O_2(g)\rightarrow 4NO(g)+6H_2O(g)$

By stoichiometry of the reaction:

4 moles of ammonia produces 6 moles of water.

So, 1.75 moles of ammonia will produce = $\frac{6}{4}\times 1.75=2.625mol$ of water.

Now, calculating the mass of water by using equation 1, we get:

Molar mass of water = 18 g/mol

Moles of water = 2.625 moles

Putting values in equation 1, we get:

$2.625mol=\frac{\text{Mass of water}}{18g/mol}\\\\\text{Mass of water}=47.25g$

Hence, the mass of water produced in the reaction is 47.25 grams.

3 0

3 years ago

Given: 2H2O2 → 2H2O + O2 structure of H2O2: H–O–O–H Bond Bond Energy (kJ/mol) O–H 459 O=O 494 O–O 142 Based on the given bond en

ICE Princess25 [194]

Answer:

B. - 210 kJ

Explanation:

∵ ΔHrxn = ∑(bond energies)products - ∑(bond energies)reactants.

The bond formation in the products releases energy (exothermic).

The bond breaking in the reactants requires energy (endothermic).

The products:

H₂O contains 2 O-H (- 459 kJ/mol) bonds.

O₂ contain 1 O=O (- 494 kJ/mol) bond.

The reactants:

H₂O₂ contain 2 O–H (459 kJ/mol) bonds and 1 O–O (142 kJ/mol) bond.

∵ ΔHrxn = ∑(bond energies)products - ∑(bond energies)reactants.

∴ ΔHrxn = [2 (2 x (O–H bond energy) + (1 x (O=O bond energy)] - 2 [(2 x (O–H bond energy) + (1 x (O–O bond energy)] = [2 (2 x - 459 kJ/mol) + (1 x - 494 kJ/mol)] - 2 [(2 x 459 kJ/mol) + (1 x 142 kJ/mol)] = (- 2330 kJ) + (2120 kJ) = - 210 kJ.

5 0

3 years ago

A certain metal M forms a soluble sulfate salt MSO, Suppose the left half cell of a galvanic cell apparatus is filled with a 3.0

bija089 [108]

Answer:

E = 0.062 V

Explanation:

(a) See the attached file for the answer

(b)

Calculating the voltage (E) using the formula;

E = - (2.303RT/nf)log Cathode/Anode

Where,

R = 8.314 J/K/mol

T = 35°C = 308 K

F- Faraday's constant = 96500 C/mol,

n = number of moles of electron = 2

Substituting, we have

E = -(2.303 * 8.314 *308/2*96500) *log (0.03/3)

= -0.031 * -2

= 0.062V

Therefore, the voltmeter will show a voltage of 0.062 V

5 0

3 years ago

State the types of change that take place in each of the following

atroni [7]

Answer:

Chemical changes

Explanation:

a)Burning a piece of charcoal - chemical change

b) Heating copper (ii) carbonate strongly - chemical change

c) Heating Zinc oxide strongly - chemical change

The given types of reaction indicates chemical changes. A chemical change is one in which a new kind of matter is formed. It is always accompanied by energy changes. The process is not easily reversible and hence, it is a permanent procedure.

Burning of charcoal produces a new kind of produces in the combustion process.

Both heating of copper(ii)carbonate strongly and zinc oxide will lead to a decomposition reaction in which new compounds are formed.

4 0

3 years ago