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2 years ago

Which statement about the periodic table is true?

Chemistry

1 answer:

dedylja [7]2 years ago

8 0

Answer

Two different elements have similar chemical properties when they have the same number of valence electrons in their outermost energy level. ... Elements in the same column of the Periodic Table have the same number of valence electrons – that's why they have similar chemical properties.

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Calculate the relative atomic mass of M

aalyn [17]

Answer:

63.55

Explanation:

relative atomic mass=(mass of isotope1×relative abundance)+(mass of isotope 2×relative abundance)/100

r.a.m=(62.93×69.09)+(64.93×30.91)/100

=(4347.8337)+(2006.9863)/100

=6354.82/100

=63.55

7 0

3 years ago

A sample of xenon occupies a volume of 736 mL at 2.02 atm and 1 °C. If the volume is changed to 416 mL and the temperature is ch

kozerog [31]

Answer:

$\large \boxed{\text{4.63 atm}}$

Explanation:

To solve this problem, we can use the Combined Gas Laws:

$\dfrac{p_{1}V_{1} }{n_{1}T_{1}} = \dfrac{p_{2}V_{2} }{n_{2}T_{2}}$

Data:

p₁ = 2.02 atm; V₁ = 736 mL; n₁ = n₁; T₁ = 1 °C

p₂ = ?; V₂ = 416 mL; n₂ = n₁; T₂ = 82 °C

Calculations:

(a) Convert the temperatures to kelvins

T₁ = ( 1 + 273.15) K = 274.15 K

T₂ = (82 + 273.15) K = 355.15 K

(b) Calculate the new pressure

$\begin{array}{rcl}\dfrac{p_{1}V_{1}}{n_{1} T_{1}} & = & \dfrac{p_{2}V_{2}}{n_{2} T_{2}}\\\\\dfrac{\text{2.02 atm}\times \text{736 mL}}{n _{1}\times \text{274.15 K}} & = &\dfrac{p_{2}\times \text{416 mL}}{n _{1}\times \text{355.15 K}}\\\\\text{5.423 atm} & = &1.171{p_{2}}\\p_{2} & = & \dfrac{\text{5.423 atm}}{1.171}\\\\ & = & \textbf{4.63 atm} \\\end{array}\\\text{The new pressure will be $\large \boxed{\textbf{4.63 atm}}$}}$

6 0

2 years ago

Help i give more point this time

dmitriy555 [2]

Answer:

It's a type of chemical bond that emerges because of electrostatic force between electrons and positive metal charges.

Explanation:

I don't know if this is what you are looking for but i don't mind if you copy it.

3 0

3 years ago

The tallest mast in the world is the KTHI-TVmast in Branchard, which measures 2063 feet , what is the expressed in meter?

Amanda [17]

1ft=.3048meter

So if we have 2063ft and want it in meters we just do a simple unit conversion.

(2063ft)(.3048meters/1ft)=628.8meters. Here ft cancel out and leave us with meter units.

Any questions please feel free to ask. Thank you.

8 0

3 years ago

Identify the oxidized and reduced forms from the following pairs:

Luden [163]

Answer:

1. NAD⁺ is the oxidized form and NADH is the reduced form

2. Pyruvate is the oxidized form and Lactate is the reduced form.

3. Oxaloacetate is the oxidized form and Malate is the reduced form.

4. Fumarate is the oxidized form and Succinate is the reduced form.

5. FMN is the oxidized form and FMNH₂ is the reduced form

6. α-ketoglutarate is the oxidized form and Isocitrate is the reduced form.

7. O₂ is the oxidized form and H₂O₂ is the reduced form.

Explanation:

Oxidation is the gain of oxygen or loss of electrons or hydrogen. Whereas, reduction is the loss of oxygen or gain of electrons or hydrogen.

1. NAD⁺/NADH

NAD⁺ is the oxidized form and NADH is the reduced form of Nicotinamide adenine dinucleotide, NAD.

Therefore, NAD⁺ gets reduced to NADH by accepting electrons and proton.

NAD⁺ + 2 e⁻ + H⁺ → NADH

2. Pyruvate/lactate

Pyruvate, CH₃COCOO⁻, is the conjugate base of Pyruvic acid.

Lactate, CH ₃CH(OH)COO⁻, is the conjugate base of Lactic acid.

Reduction of Pyruvate to lactate:

CH₃COCOO⁻ + NADH ⇌ CH ₃CH(OH)COO⁻ + NAD⁺

This reaction is catalyzed by the enzyme lactate dehydrogenase.

Therefore, Pyruvate is the oxidized form and Lactate is the reduced form.

3. Malate/oxaloacetate

Oxaloacetate, ⁻O₂CC(O)CH₂CO₂⁻, is the conjugate base of oxaloacetic acid.

Malate,⁻O₂CCH(OH)CH₂CO₂⁻, is the conjugate base of Malic acid.

Oxidation of Malate to Oxaloacetate:

⁻O₂CCH(OH)CH₂CO₂⁻ + NAD⁺ ⇌ ⁻O₂CC(O)CH₂CO₂⁻ + NADH

This reaction is catalyzed by the enzyme malate dehydrogenase.

Therefore, Oxaloacetate is the oxidized form and Malate is the reduced form.

4. Fumarate/succinate

Fumarate, ⁻O₂CCH=CHCO₂⁻, is the conjugate base of Fumaric acid.

Succinate, ⁻O₂CCH₂CH₂CO₂⁻, is the conjugate base of Succinic acid.

Oxidation of succinate to fumarate:

⁻O₂CCH₂CH₂CO₂⁻ + FAD ⇌ ⁻O₂CCH=CHCO₂⁻ + FADH₂

This reaction is catalyzed by the enzyme succinate dehydrogenase.

Therefore, fumarate is the oxidized form and succinate is the reduced form.

5. FMN/FMNH₂

FMN is the oxidized form and FMNH₂ is the reduced form of riboflavin-5′-phosphate or Flavin mononucleotide.

Therefore, FMN gets reduced to FMNH₂ by accepting electrons and proton.

FMN + 2 e⁻ + 2H⁺ → FMNH₂

6. α-ketoglutarate/isocitrate

α-ketoglutarate, ⁻O₂CC(O)CH₂CH₂CO₂⁻, is the conjugate base of α-Ketoglutaric acid.

Isocitrate, ⁻O₂CCH(OH)CH(CO₂⁻)CH₂CO₂⁻, is the conjugate base Isocitric acid.

Oxidation of Isocitrate to α-ketoglutarate:

⁻O₂CCH(OH)CH(CO₂⁻)CH₂CO₂⁻ + NAD⁺ → ⁻O₂CC(O)CH₂CH₂CO₂⁻ + CO₂ + NADH

This reaction is catalyzed by the enzyme Isocitrate dehydrogenase.

Therefore, α-ketoglutarate is the oxidized form and Isocitrate is the reduced form.

7. H₂O₂/O₂

Hydrogen peroxide, H₂O₂, is synthesized from hydrogen (H₂) and oxygen (O₂) in the presence of a catalyst.

H₂ + O₂ → H₂O₂

Oxygen gets reduced from 0 oxidation state in O₂ to -1 oxidation state in H₂O₂.

Therefore, O₂ is the oxidized form and H₂O₂ is the reduced form.

8 0

3 years ago