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3 years ago

212 pb 82 is the isotope notation for iron. what is the atomic number, mass number, and number of both protons and neutrons?

Chemistry

1 answer:

o-na [289]3 years ago

5 0

Hello!

The mass number in isotope notation is denoted A, the atomic number is denoted as Z, and the element is denoted as X.

In the given isotope, the mass of the isotope is 212 amu, and the atomic number is 82.

We know that the number of electrons, and protons are equal to the atomic number. Therefore, there are 82 protons. Also, to find the number of neutrons, we subtract the atomic number from the atomic mass.

212 - 82 = 130 neutrons

Final answers:

Atomic Number: 82
Mass number: 212
Number of Protons: 82
Number of Neutrons: 130

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8. A sample of chloroform is found to contain 24.0 g of carbon,212.8 g of chlorine, and 2.02 g of hydrogen. If a second sample o

Misha Larkins [42]

Answer:

595.5

Explanation:

chloroform with 24.0 g C was 238.2 g

24g/238.2g= 60g/x

595.5

4 0

3 years ago

Determine the pHpH of an HFHF solution of each of the following concentrations. In which cases can you not make the simplifying

PIT_PIT [208]

The question is incomplete, complete question is :

Determine the pH of an HF solution of each of the following concentrations. In which cases can you not make the simplifying assumption that x is small? ( $K_a$ for HF is $6.8\times 10^{-4}$ .)

[HF] = 0.280 M

Express your answer to two decimal places.

Answer:

The pH of an 0.280 M HF solution is 1.87.

Explanation:3

Initial concentration if HF = c = 0.280 M

Dissociation constant of the HF = $K_a=6.8\times 10^{-4}$

$HF\rightleftharpoons H^++F^-$

Initially

c 0 0

At equilibrium :

(c-x) x x

The expression of disassociation constant is given as:

$K_a=\frac{[H^+][F^-]}{[HF]}$

$K_a=\frac{x\times x}{(c-x)}$

$6.8\times 10^{-4}=\frac{x^2}{(0.280 M-x)}$

Solving for x, we get:

x = 0.01346 M

So, the concentration of hydrogen ion at equilibrium is :

$[H^+]=x=0.01346 M$

The pH of the solution is ;

$pH=-\log[H^+]=-\log[0.01346 M]=1.87$

The pH of an 0.280 M HF solution is 1.87.

6 0

2 years ago

Consider the following reaction between mercury(II) chloride and oxalate ion.

Alina [70]

Answer: The rate law of the reaction is $\text{Rate}=k[HgCl_2][C_2O_4^{2-}]^2$

Explanation:

Rate law is defined as the expression which expresses the rate of the reaction in terms of molar concentration of the reactants with each term raised to the power their stoichiometric coefficient of that reactant in the balanced chemical equation.

For the given chemical equation:

$2 HgCl_2(aq.)+C_2O_4^{2-}(aq.)\rightarrow 2Cl^-(aq.)+2CO_2(g)+Hg_2Cl_2(s)$

Rate law expression for the reaction:

$\text{Rate}=k[HgCl_2]^a[C_2O_4^{2-}]^b$

where,

a = order with respect to $HgCl_2$

b = order with respect to $C_2O_4^{2-}$

Expression for rate law for first observation:

$3.2\times 10^{-5}=k(0.164)^a(0.15)^b$ ....(1)

Expression for rate law for second observation:

$2.9\times 10^{-4}=k(0.164)^a(0.45)^b$ ....(2)

Expression for rate law for third observation:

$1.4\times 10^{-4}=k(0.082)^a(0.45)^b$ ....(3)

Expression for rate law for fourth observation:

$4.8\times 10^{-5}=k(0.246)^a(0.15)^b$ ....(4)

Dividing 2 from 1, we get:

$\frac{2.9\times 10^{-4}}{3.2\times 10^{-5}}=\frac{(0.164)^a(0.45)^b}{(0.164)^a(0.15)^b}\\\\9=3^b\\b=2$

Dividing 2 from 3, we get:

$\frac{2.9\times 10^{-4}}{1.4\times 10^{-4}}=\frac{(0.164)^a(0.45)^b}{(0.082)^a(0.45)^b}\\\\2=2^a\\a=1$

Thus, the rate law becomes:

$\text{Rate}=k[HgCl_2]^1[C_2O_4^{2-}]^2$

3 0

2 years ago

Chemistry test bound theories

liq [111]

covalent bond is firmed between two atoms

5 0

2 years ago

A scientist is researching the solar system. How can the scientist best add to existing empirical evidence about the solar syste

Bogdan [553]

Answer:

The correct option is;

c. The scientist can make and record observations

Explanation:

Empirical evidence are evidences obtained by direct observation, sensual perception or direct measurement. It is the processed and useful data gathered and stored in a material form or documented to provide record of the measurement.

With the aid of empirical evidence, it is possible for researchers to find answers to question regarding topics that can vastly impact every day life.

With empirical evidence, it is possible to determine the effects of treatment in a study such as the invention of working car safety devices such as seat belts and airbags.

7 0

3 years ago