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Alex_Xolod [135]
3 years ago
11

A radioactive sample has a half-life of 5 hours. What fraction of the sample will be left after 15 hours?​

Chemistry
1 answer:
DedPeter [7]3 years ago
6 0

Explanation:

hiiiii beautiful.........

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Calculate the osmotic pressure associated with 50.0 g of an enzyme of molecular weight 98 g/mol dissolved in water to give 2600
andrew-mc [135]

Answer:

π = 4,882 atm

Explanation:

To calculate the osmotic pressure (π), the <em>Van´t Hoff equation</em> must be used, which is:

π x V = n x R x T

<em>Where: </em>

• π: Osmotic pressure, which is the difference between the levels of the solution and the pure solvent through a semipermeable membrane, which allows the passage of the solvent but not the solute

• V: Volume of the solution, in liters unit

• n: Number of moles of solute

• R: Constant of ideal gases, equal to 0.08206 L.atm / mol.K

• T: Absolute temperature, in Kelvin degrees

With the data you provide you can calculate the osmotic pressure by clearing it from the equation, we would be equal to:

π = (n x R x T) / V

However, all data must first be converted to the corresponding units in order to replace the values ​​in the equation.

<em>Solution volume ⇒ go from mL to L: </em>

1000 mL of solution ____ 1 L

2600 mL of solution _____ X = 2.6 L

Calculation: 2600 mL x 1 L / 1000 mL = 2.6 L

<em>Temperature ⇒ Go from ° C to K </em>

T (K) = t (° C) + 273.15 = 30.0 ° C + 273.15 = 303.15 K

<em>Number of moles of solute ⇒</em> <em>It can be calculated since we have the mass of the enzyme and its molecular mass: </em>

98.0 g of enzyme ____ 1 mol

50.0 g of enzyme _____ X = 0.510 moles

Calculation: 50.0 g x 1 mol / 98.0 g = 0.510 moles

Now, you can replace the values ​​in the Van´t Hoff equation and you will get the result:

 π = (n x R x T) / V

π = (0.510 mol x 0.08206 L.atm / mol.K x 303.15 K) / 2.6 L = 4.882 atm

Therefore, <em>the osmotic pressure will be 4,882 atm</em>

3 0
3 years ago
Balance this chemical equation. NH4OH AlCl3 → Al(OH)3; NH4Cl
skad [1K]
3NH4OH+AlCl3=Al(OH)3+3NH4Cl
7 0
3 years ago
Read 2 more answers
Zinc has a specific heat capacity of 0.390 J/goC. What is its molar heat capacity? Enter your answer numerically to three signif
ch4aika [34]

Answer:

The answer to your questions is  Cm = 25.5 J/mol°C  

Explanation:

Data

Heat capacity = 0.390 J/g°C

Molar heat capacity = ?

Process

1.- Look for the atomic number of Zinc

     Z = 65.4 g/mol

2.- Convert heat capacity to molar heat capacity

       (0.390 J/g°C)(65.4 g/mol)

- Simplify and result

   Cm = 25.5 J/mol°C  

3 0
3 years ago
Which observation does not indicate that a chemical reaction has occurred?
castortr0y [4]

Answer:

change in the total mass of substances

6 0
3 years ago
A gas used to extinguish fires is composed of 75 % CO2 and 25 % N2. It is stored in a 5 m3 tank at 300 kPa and 25 °C. What is th
tatyana61 [14]

Answer : The partial pressure of the CO_2 in the tank in psia is, 32.6 psia.

Explanation :

As we are given 75 % CO_2 and 25 % N_2 in terms of volume.

First we have to calculate the moles of CO_2 and N_2.

\text{Moles of }CO_2=\frac{\text{Volume of }CO_2}{\text{Volume at STP}}=\frac{75}{22.4}=3.35mole

\text{Moles of }N_2=\frac{\text{Volume of }N_2}{\text{Volume at STP}}=\frac{25}{22.4}=1.12mole

Now we have to calculate the mole fraction of CO_2.

\text{Mole fraction of }CO_2=\frac{\text{Moles of }CO_2}{\text{Moles of }CO_2+\text{Moles of }N_2}

\text{Mole fraction of }CO_2=\frac{3.35}{3.35+1.12}=0.75

Now we have to calculate the partial pressure of the CO_2 gas.

\text{Partial pressure of }CO_2=\text{Mole fraction of }CO_2\times \text{Total pressure of gas}

\text{Partial pressure of }CO_2=0.75mole\times 300Kpa=225Kpa=225Kpa\times \frac{0.145\text{ psia}}{1Kpa}=32.625\text{ psia}

conversion used : (1 Kpa = 0.145 psia)

Therefore, the partial pressure of the CO_2 in the tank in psia is, 32.6 psia.

3 0
3 years ago
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