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sergeinik [125]
3 years ago
13

What is the sum of 2.7 g and 2.47g expressed in the correct number of significant digits

Chemistry
2 answers:
Anastasy [175]3 years ago
6 0

Answer :  The answer will be, 5.2 g

Explanation :

Significant figures : The figures in a number which express the value -the magnitude of a quantity to a specific degree of accuracy is known as significant digits.

The rule apply for the addition and subtraction is :

The least precise number present after the decimal point determines the number of significant figures in the answer.

As we are given that the sum of 2.7 g and 2.47 g.

2.7g+2.47g

\Rightarrow 5.17g

In the given expression, 2.7 has 2 significant figures and 2.47 has 2 significant figures. From this we conclude that least precise number present after the decimal point is 1.

Thus, the answer will be \Rightarrow 5.2g

NeTakaya3 years ago
5 0
In order to get the sum of 2.7 and 2.47, we will add both numbers. So, 2.7 plus 2.47 would be 5.17. And the correct number of significant digits in this number is still the same, 5.17, so we have three significant numbers. Why? There are three rules in identifying the significant figures: 1. Non zeros are always significant (which this applies in our sum above). 2. Any zeros in between significant numbers are always significant. 3. <span> The final zero or zeros in the decimal portion only are significant.</span>
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Harlamova29_29 [7]
Following reaction is involved in above system
HOCl(aq)  ↔  H+(aq) + OCl-<span>(aq)
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</span>
Now, if the system is obeys 1st order kinetics we have
K  = [OCl-][H+<span>]/[HOCl]   ............. (1)
</span>∴ [HOCl-] / [OCl-] = [H+] (1 / 3.0 * 10-8<span>)   ............. (2)
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and now considering that system is obeying 2nd order kinetics, we have
K  = [OH-][HOCl-] / [OCl-] ................. (3<span>)
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3 years ago
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Arrange the following H atom electron transitions in order of decreasing wavelength of the photon absorbed or emitted:
Katyanochek1 [597]

The decreasing order of wavelengths of the photons emitted or absorbed by the H atom is : b → c → a → d

Rydberg's formula :

                                   \frac{1}{\lambda} = R_h (\frac{1}{n_1^2}-\frac{1}{n_2^2} ),

where  λ is the wavelength of the photon emitted or absorbed from an H atom electron transition from n_1 to n_2 and R_h = 109677 is the Rydberg Constant. Here n_1 and  n_2 represents the transitions.

(a) n_1 =2 to n_2 = infinity

            \frac{1}{\lambda} = 109677\times (\frac{1}{2^2}-\frac{1}{\infty^2}  ) = 109677/4     [since 1/infinity = 0] Therefore, \lambda = 4 / 109677 = 0.00003647 m

(b) n_1=4 to  n_2 = 20

           \frac{1}{\lambda} = 109677\times (\frac{1}{4^2}-\frac{1}{20^2}  ) = 6580.62

Therefore,  \lambda = 1 / 6580.62 = 0.000152 m

(c) n_1=3 to  n_2 = 10

          \frac{1}{\lambda} = 109677\times (\frac{1}{3^2}-\frac{1}{10^2}  ) = 11089.56

Therefore,  \lambda = 1 / 11089.56 = 0.00009 m

(d)  n_1=2 to  n_2 = 1

          \frac{1}{\lambda} = 109677\times (\frac{1}{2^2}-\frac{1}{1^2}  ) = - 82257.75

Therefore,  \lambda = 1 /82257.75  = - 0.0000121 m  

[Even though there is a negative sign, the magnitude is only considered because the sign denotes that energy is emitted.]

So the decreasing order of wavelength of the photon absorbed or emitted is b → c → a → d.

Learn more about the Rydberg's formula athttps://brainly.com/question/14649374

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8 0
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Answer:

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Empirical Formula:

Empirical formula is the simplest ration of atoms in the molecule but not all numbers of atoms in a compound.

So,

Tha ration of the molecular formula should be divided by whole number to get the simplest ratio of molecule

For Example

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Now

Look at the ratio of these three atoms in the compound

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Divide the ratio by two to get simplest ratio

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So the empirical formula will be

                     Empirical formula of C₂H₆O₂ = CH₃O

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