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Arlecino [84]
3 years ago
10

All of the following show a periodic pattern except

Chemistry
1 answer:
AlekseyPX3 years ago
4 0
<span>A. the dog ate everyone of his play toys</span>
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This is a picture of a large sheet of ice that moves very slowly across the land. This sheet of ice covers the land and is
Ilya [14]

Answer: I think A

Explanation:

3 0
3 years ago
A mixture of CuSO4 · 5H2O and MgSO4 · 7H2O is heated until all the water is lost. If 5.127 g of the mixture gives 2.817 g of the
Nadusha1986 [10]

Answer:

Let the mixture is X% by mass of CuSO

4

.5H

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O and 100 - X % by mass of MgSO

4

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O. 5.0 g of mixture will contain 0.05X g CuSO

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2

O and 5.0 - 0.05X g MgSO

4

.7H

2

O

The molar masses of CuSO

4

.5H

2

O and MgSO

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.7H

2

O are 249.7 g/mol and 246.5 g/mol respectively.

The number of moles of CuSO

4

.5H

2

O=

249.7

0.05X

=2.00×10

−4

X moles.

Explanation:

Pls mark it as branliest answere thanks

3 0
3 years ago
If the K a Ka of a monoprotic weak acid is 7.3 × 10 − 6 , 7.3×10−6, what is the pH pH of a 0.40 M 0.40 M solution of this acid?
olga_2 [115]

Answer:

pH =3.8

Explanation:

Lets call the monoprotic weak acid HA, the dissociation equilibria in water will be:

HA + H₂O   ⇄ H₃O⁺ + A⁻    with  Ka = [ H₃O⁺] x [A⁻]/ [HA]

The pH is the negative log of the H₃O⁺ concentration, we know the equilibrium constant, Ka and the original acid concentration. So we will need to find the [H₃O⁺] to solve this question.

In order to do that lets set up the ICE table helper which accounts for the species at equilibrium:

                          HA                                   H₃O⁺                          A⁻          

Initial, M             0.40                                   0                              0

Change , M          -x                                     +x                            +x

Equilibrium, M    0.40 - x                              x                               x

Lets express these concentrations in terms of the equilibrium constant:

Ka = x² / (0.40 - x )

Now the equilibrium constant is so small ( very little dissociation of HA ) that is safe to approximate 0.40 - x to 0.40,

7.3 x 10⁻⁶ = x² / 0.40  ⇒ x = √( 7.3 x 10⁻⁶ x 0.40 ) = 1.71 x 10⁻³

[H₃O⁺] = 1.71 x 10⁻³

Indeed 1.71 x 10⁻³ is small compared to 0.40 (0.4 %). To be a good approximation our value should be less or equal to 5 %.

pH = - log ( 1.71 x 10⁻³ ) = 3.8

Note: when the aprroximation is greater than 5 % we will need to solve the resulting quadratic equation.

4 0
3 years ago
the carbon atom which becomes asymmetric when the straight chain form of monosaccharide change into ring form is known as____\
amid [387]

Answer:

CARBOHYDRATES AND CARBOHYDRATE METABOLISM

4 0
2 years ago
Which of the following would have the largest pKa?
garri49 [273]

Answer:

CH3CH2NH3+/CH3CH2NH2 would have the largest pKa

Explanation:

To answer this question we must know Kb of CH3CH2NH2 is 5.6x10⁻⁴, and for C6H5NH2 is 4.0x10⁻¹⁰. And the CH3CH2NH3+ and C6H5NH3+ are related with these substances because are their conjugate base. That means:

pKa of  CH3CH2NH3+ =  CH3CH2NH2;  C6H5NH3+ =  C6H5NH2

Also, Kw / Kb = Ka

Thus:

pKa of CH3CH2NH3+/CH3CH2NH2 is:

Kw / kb = Ka = 1.79x10⁻¹¹

-log Ka = pKa

pKa = 10.75

pKa of C6H5NH3+/ C6H5NH2 is:

Kw / kb = Ka = 2.5x10⁻⁵

-log Ka = pKa

pKa = 4.6

That means CH3CH2NH3+/CH3CH2NH2 would have the largest pKa

5 0
3 years ago
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