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denis23 [38]
3 years ago
13

Find the molar mass of potassium dichromate, K2Cr2O7

Chemistry
1 answer:
prisoha [69]3 years ago
6 0
The molar mass of K is 39, Cr is 52, and O is 16. The rough calculation of these numbers are 294. 
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What Is Precision? The Degree Of Accuracy In A Measurement
Artemon [7]

Answer:

Precision refers to how close two or more measurements are to each other, regardless whether those measurements are accurate or not.

Accuracy refers to how closely the measured value of a quantity corresponds to its “true” value.

Explanation:

4 0
3 years ago
explain how solar radiation and convection currents on Earth. Describe how solar radiation and convection currents work together
Pepsi [2]

Answer:

Convection is the transfer of heat energy in a fluid. ... Air in the atmosphere acts as a fluid. The sun's radiation strikes the ground, thus warming the rocks.

Explanation:

3 0
3 years ago
Read 2 more answers
Cierto elemento presenta dos isótopos cuyos números de masa suman 110 y cuyos números de neutrones suman 58 ¿Cuál es el número a
Anettt [7]

Answer:

El número atómico de cada uno de los átomos es 26

Explanation:

El número de masa es la suma de las masas del protón y el neutrón de un átomo.

El número atómico es el número de protones en el átomo.

Los parámetros dados son;

La suma del número másico de ambos átomos = 110

La suma de los neutrones = 58

Por lo tanto, sea el número de protones y neutrones en un isótopo = P₁ y N₁ y el número de protones y neutrones en el otro isótopo = P₂ y N₂

Tenemos;

 P₁ + N₁ + P₂ + N₂ = 110

N₁ + N₂ = 58

Por lo tanto;

P₁ + P₂ = 110 - (N₁ + N₂)

P₁ + P₂ = 110 - 58 = 52

Dado que los isótopos son del mismo elemento, sus protones serán iguales, por lo tanto;

P₁ = P₂

P₁ + P₂ = P₁ + P₁ = 2 × P₁

P₁ + P₂ = 52

2 × P₁ = 52

P₁ = 52/2 = 26 = P₂

El número atómico de ambos átomos es el número de protones en el átomo que es 26.

El número atómico del elemento del átomo es 26

6 0
3 years ago
The compound Xe(CF3)2 decomposes in afirst-order reaction to elemental Xe with a half-life of 30. min.If you place 7.50 mg of Xe
Irina-Kira [14]

Answer:

t=147.24\ min

Explanation:

Given that:

Half life = 30 min

t_{1/2}=\frac{\ln2}{k}

Where, k is rate constant

So,  

k=\frac{\ln2}{t_{1/2}}

k=\frac{\ln2}{30}\ min^{-1}

The rate constant, k = 0.0231 min⁻¹

Using integrated rate law for first order kinetics as:

[A_t]=[A_0]e^{-kt}

Where,  

[A_t] is the concentration at time t

[A_0] is the initial concentration

Given that:

The rate constant, k = 0.0231 min⁻¹

Initial concentration [A_0] = 7.50 mg

Final concentration [A_t] = 0.25 mg

Time = ?

Applying in the above equation, we get that:-

0.25=7.50e^{-0.0231\times t}

750e^{-0.0231t}=25

750e^{-0.0231t}=25

x=\frac{\ln \left(30\right)}{0.0231}

t=147.24\ min

6 0
3 years ago
A chemist dissolves 867. mg of pure barium hydroxide in enough water to make up 170. mL of solution. Calculate the pH of the sol
Ilya [14]

Answer: The pH of the solution is 11.2

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

Molarity=\frac{n\times 1000}{V_s}

where,

n = moles of solute

V_s = volume of solution in ml

moles of Ba(OH)_2 = \frac{\text {given mass}}{\text {Molar mass}}=\frac{0.867g}{171g/mol}=0.00507mol         (1g=1000mg)

Now put all the given values in the formula of molality, we get

Molarity=\frac{0.00507\times 1000}{170}

Molarity=0.0298

pH or pOH is the measure of acidity or alkalinity of a solution.

pH is calculated by taking negative logarithm of hydrogen ion concentration.

pOH=-\log [OH^-]

Ba(OH)_2\rightarrow Ba^{2+}+2OH^{-}

According to stoichiometry,

1 mole of Ba(OH)_2 gives 2 mole of OH^-

Thus 0.0298 moles of Ba(OH)_2 gives =\frac{2}{1}\times 0.0298=0.0596 moles of OH^-

Putting in the values:

pOH=-\log[0.0596]=2.82

pH+pOH=14

pH=14-2.82

pH=11.2

Thus the pH of the solution is 11.2

8 0
3 years ago
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