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3 years ago

Cho một thực phẩm có độ ẩm tương đối là 81%, hỏi hoạt độ của nước của thực phẩm đó là bao nhiêu?

Chemistry

1 answer:

spayn [35]3 years ago

6 0

Explanation:

Given a food with a relative humidity of 81%, what is the water activity of that food?

The water activity of a food can be determined by using the formula:

water activity=relative humidity of food / 100

$water activity of a food=\frac{relative humidity of food }{100} \\=81/100\\=0.81$

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Given that Kp = 3.5 x 10-4 for the reaction 2 CO(g) <=> C(graphite) + CO2(g), what is the partial pressure of CO2(g) at eq

spin [16.1K]

Answer: The partial pressure of carbon dioxide at equilibrium is 0.0056 atm

Explanation:

The given chemical equation follows:

$2CO(g)\rightleftharpoons C\text{ (graphite)}+CO_2(g)$

Initial: 4.00

At eqllm: 4.00-2x x x

The expression of $K_p$ for above reaction follows:

$K_p=\frac{p_{CO_2}}{(p_{CO})^2}$

The partial pressure of pure solids and liquids are taken as 1 in the equilibrium constant expression.

We are given:

$K_p=3.5\times 10^{-4}$

Putting values in above expression, we get:

$3.5\times 10^{-4}=\frac{x}{(4-2x)^2}\\\\x=0.0056,718.28$

Neglecting the value of x = 718.28 because equilibrium pressure cannot be greater than initial pressure

Partial pressure of $CO_2$ = 0.0056 atm

Hence, the partial pressure of carbon dioxide at equilibrium is 0.0056 atm

4 0

3 years ago

An unknown quantity of methane gas, CHA, is held in a 2.00-liter container at 77°C. The pressure inside the container is 3.00 am

kolbaska11 [484]

Answer:

$0.21\text{ mol}$

Explanation:

Here, we want to calculate the number of moles of methane in the container

From the ideal gas law:

$\begin{gathered} PV\text{ = nRT} \\ n\text{ = }\frac{PV}{RT} \end{gathered}$

where:

P is the pressure inside the container which is 3 atm

V is the volume of the container which is 2 L

R is the molar gas constant which is 0.0821 Latm/mol.k

T is the temperature in Kelvin (we convert the temperature in Celsius by adding 273 : 273 + 77 = 350 K)

n is the number of moles that we want to calculate

Substituting the values, we have it that:

$n=\text{ }\frac{3\times2}{0.0821\text{ }\times350}\text{ = 0.21 mol}$

6 0

1 year ago

victus00 [196]

Answer:

This isotope has 59 electrons giving it a charge of -2.

Explanation:

To find this we have to understand isotope relates to the mass of the nucleus. This isotope has 59 electrons to counter the protons and give it a negative charge.

6 0

3 years ago

An experiment in a general chemistry laboratory calls for a 2.00 M solution of HCL. How many mL of 11.9 M HCL would be required

Annette [7]

Answer: The volume of concentrated solution required is 42 mL

Explanation:

To calculate the molarity of the diluted solution, we use the equation:

$M_1V_1=M_2V_2$

where,

$M_1\text{ and }V_1$ are the molarity and volume of the concentrated solution

$M_2\text{ and }V_2$ are the molarity and volume of diluted solution

We are given:

$M_1=11.9M\\V_1=?mL\\M_2=2.0M\\V_2=250mL$

Putting values in above equation, we get:

$11.9\times V_1=2.0\times 250\\\\V_1=42mL$

Hence, the volume of concentrated solution required is 42 mL

3 0

3 years ago

In the reaction, H2SO4. +. H2O -------> HSO4- +. H3O+ The Base is ____________ a H2SO4 b H3O+ c H2O d HSO4-

expeople1 [14]

The base is H2O because it is accepting an H+ ion.

5 0

3 years ago