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vladimir2022
21 day ago
14

Dumbledore decides to gives a surprise demonstration. He starts with a hydrate of Na2CO3 which has a mass of 4.31 g before heati

ng. After he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. He asks everyone in class to determine the integer x in the hydrate: Na2CO3·xH2O; you should do this also. Round your answer to the nearest integ
Chemistry
1 answer:
eduard [2.5K]21 day ago
7 0
The formula is Na₂CO₃·2H₂O. To find the integer x representing the amount of crystallization water, we analyze the given mass before and after heating.
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A sealed 10.0 L flask at 400 K contains equimolar amounts of ethane and propanol in gaseous form. Which of the following stateme
castortr0y [2743]

Answer:

(C) The average speed of molecules in ethane is the same as that of propanol.

Explanation:

In gas behavior, temperature is directly linked with speed. At a constant temperature, speed remains consistent. Also, we understand that ideal gases exhibit uniform behavior, irrespective of their type.

8 0
18 days ago
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Find the age ttt of a sample, if the total mass of carbon in the sample is mcmcm_c, the activity of the sample is AAA, the curre
castortr0y [2743]

Answer:

Explanation:

In a desert cave, an artifact has been discovered. The anthropologists investigating this artifact want to determine its age. They note that the current activity level of the artifact is 9.25 decays/s, and the carbon mass present is 0.100 kg. To ascertain the artifact's age, they will employ specific constants:

r=1.2

The formula for carbon 14 activity is

A=A_0e^{\lambda t}

where,

A_0 is the initial activity of the substance

Now, solve for t

-\lambda t=In\frac{A}{A_0}

t=-\frac{1}{\lambda} In(\frac{A}{A_0} )

=-\frac{1}{\lambda} In(\frac{A}{\lambda r(\frac{m_c}{m_a} )} )

since,

A_0=\lambda r(\frac{m_c}{m_a} )

=-\frac{1}{\lambda} In(\frac{A\ m_a}{\lambda r m_c} )

Thus, the age of the artifact is

=-\frac{1}{\lambda} In(\frac{A\ m_a}{\lambda r m_c} )

=-\frac{1}{1.21\times 10^{-4}} In(\frac{(9.25)(2.32\times 10^{-26}}{1.21\times 10^{-4}(\frac{1}{3.15569\times10^7} )(1.2\times 10^{-12})(0.100)}} )\\\\=6303.4 \ years

to two significant figures = 6300 years

4 0
1 month ago
(a) The original value of the reaction quotient, Qc, for the reaction of H2(g) and I2(g) to form HI(g) (before any reactions tak
KiRa [2726]

Response:

Here's my calculation

Clarification:

Assume the starting concentrations of H₂ and I₂ are 0.030 and 0.015 mol·L⁻¹, respectively.

We need to determine the initial concentration of HI.

1. We will need a chemical equation with concentrations, so let's compile all the information in one location.

H₂ + I₂ ⇌ 2HI

I/mol·L⁻¹: 0.30 0.15 x

2. Calculate the concentration of HI

Q_{\text{c}} = \dfrac{\text{[HI]}^{2}} {\text{[H$_{2}$][I$_{2}$]}} =\dfrac{x^{2}}{0.30 \times 0.15} =  5.56\\\\x^{2} = 0.30 \times 0.15 \times 5.56 = 0.250\\x = \sqrt{0.250} = \textbf{0.50 mol/L}\\\text{The initial concentration of HI is $\large \boxed{\textbf{0.50 mol/L}}$}

3. Plot the initial values

The graph below visualizes the initial concentrations as plotted on the vertical axis.

7 0
1 month ago
At STP, the element oxygen can exist as either O2 or O3 gas molecules. These two forms of the element have(1) the same chemical
Anarel [2605]
O2 and O3 represent different forms of Oxygen; therefore, they exhibit (4) distinct chemical and physical properties..
5 0
28 days ago
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What is [h3o ] in a solution of 0.25 m ch3co2h and 0.030 m nach3co2?
Anarel [2605]

Hello!

To find [H₃O⁺], we will employ the Henderson-Hasselbalch equation, as this involves an acid and its conjugate base:

pH=pKa+log( \frac{[A^{-}] }{[HA]} )

pH=4,76+log( \frac{0,030M}{0,25M} ) \\ \\ pH=3,84

Next, we derive [H₃O⁺] using the definition of pH:

pH=-log[H_3O^{+}]

[H_3O^{+}] = 10^{-pH} =10^{-3,84}=0,00014 M

Hence, the concentration of [H₃O⁺] comes out to be 0.00014 M

Wishing you a good day!

4 0
1 month ago
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