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2 years ago

Two atoms of the same element cannot have different numbers of _____.

2 answers:

7 0

Protons is what indicates the element

Different numbers of neutrons/ electrons would result in a charged elements (isotope)

marysya [2.9K]2 years ago

6 0

Answer:

c. protons

Explanation:

A "proton" is a subatomic particle that is stable and is positively-charged. You will identify the number of protons that is present in the nucleus of a chemical element by its "atomic number." It gives us an identity of the element, therefore, every atom of the same element have the "same" number of protons. For example, the number of protons for "Hydrogen" is 1. This means that even if you have two atoms of Hydrogen, each of them has "1" as the number of proton.

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Cells contain parts known as organelles these parts are specialized. What does this mean?

Eddi Din [679]

Answer:

because they devlop our organs

7 0

2 years ago

Suppose that a dependent quantity increases when the independent quantity is decreased. This kind of proportional relationship b

Anna71 [15]

I thinks it’s not this article we should cajnges it

3 0

2 years ago

Which one of the following best represents the predicted approximate chemical shift and coupling:

mezya [45]

Answer:

C. 3.40 ppm, singlet

Explanation:

Given the information from the question .we have to select the best representation for represents the predicted approximate chemical shift and coupling for hydrogen(s). In this case, there is no neighboring hydrogen .Thus there won’t be any split .the best option answer is C. 3.40 ppm, singlet . Therefore the correct answer or option is C. 3.40 ppm, singlet.

4 0

3 years ago

0.2640 g of sodium oxalate is dissolved in a flask and requires 30.74 mL of potassium

Free_Kalibri [48]

Moles of potassium permanganate = 0.0008

<h3>Further explanation </h3>

Titration is a procedure for determining the concentration of a solution by reacting with another solution which is known to be concentrated (usually a standard solution). Determination of the endpoint/equivalence point of the reaction can use indicators according to the appropriate pH range

Reaction

5Na2C2O4(aq) + 2KMnO4(aq) + 8H2SO4(aq) ---> 2MnSO4(aq) + K2SO4(aq) + 5Na2SO4(aq) + 10CO2(g) + 8H2O(1)

The end point ⇒titrant and analyte moles equal

titrant : potassium permanganate-KMnO4

analyte : sodium oxalate - Na2C2O4

so moles of KMnO4 = moles of Na2C2O4

moles of Na2C2O4(mass = 0.2640 g, MW=134 g/mol) :

$\tt mol=\dfrac{mass}{MW}\\\\mol=\dfrac{0.264}{134 g/mol}\\\\mol=0.002$

From equation, mol ratio Na2C2O4 : KMnO4 = 5 : 2, so mol KMnO4 :

$\tt \dfrac{2}{5}\times 0.002=0.0008$

6 0

2 years ago

(b) The conductivity of a 0.01 mol dm–3 solution of a monobasic organic acid in water is 5.07 × 10–2 S m–1. If the molar conduct

Zarrin [17]

Explanation:

The given data is as follows.

$\Lambda^{o}_{m}$ (NaCl) = $1.264 \times 10^{-2}$

$\Lambda^{o}_{m}$ (H-O=C-ONO) = $1.046 \times 10^{-2}$

$\Lambda^{o}_{m}$ (HCl) = $4.261 \times 10^{-2}$

Conductivity of monobasic acid is $5.07 \times 10^{-2} S m^{-1}$

Concentration = 0.01 $mol/dm^{3}$

Therefore, molar conductivity ( $\Lambda_{m}$ ) of monobasic acid is calculated as follows.

$\Lambda_{m} = \frac{conductivity}{concentration}$

= $\frac{5.07 \times 10^{-2} S m^{-1}}{0.01 mol/dm^{3}}$

= $\frac{5.07 \times 10^{-2} S m^{-1}}{0.01 mol \times 10^{3}}$

= $5.07 \times 10^{-3} S m^{2} mol^{-1}$

Also, $\Lambda^{o}_{m}$ = $\Lambda^{o}_{m}_{(HCl)} + \Lambda^{o}_{m}_{(H-O=C-ONO)} - \Lambda^{o}_{m}_{(NaCl)}$

= $4.261 \times 10^{-2} + 1.046 \times 10^{-2} - 1.264 \times 10^{-2}$

= $4.043 \times 10^{-2} S m^{2} mol^{-1}$

Relation between degree of dissociation and molar conductivity is as follows.

$\alpha = \frac{\Lambda_{m}}{\Lambda^{o}_{m}}$

= $\frac{5.07 \times 10^{-2} S m^{-1}}{4.043 \times 10^{-2} S m^{2} mol^{-1}}$

= 0.1254

Whereas relation between acid dissociation constant and degree of dissociation is as follows.

K = $\frac{c \times \alpha^{2}}{1 - \alpha}$

Putting the values into the above formula we get the following.

K = $\frac{c \times \alpha^{2}}{1 - \alpha}$

= $\frac{0.01 \times (0.1254)^{2}}{1 - 0.1254}$

= $0.017973 \times 10^{-2}$

= $1.7973 \times 10^{-4}$

Hence, the acid dissociation constant is $1.7973 \times 10^{-4}$ .

Also, relation between $pK_{a}$ and $K_{a}$ is as follows.

$pK_{a} = -log K_{a}$

= $-log (1.7973 \times 10^{-4})$

= 3.7454

Therefore, value of $pK_{a}$ is 3.7454.

3 0

2 years ago