N2(g) + 2 O2(g) → 2 NO2(g)

The treatment dosage will not be effective for 1 week.

A balanced nuclear reaction for the radioactive decay of Yittrium-90 (90 Y 39 ) is:  90 Y 39  ⟶  90 Zr 40  +  0 β − 1b)Given dataMass of sample, m = 2.5 mgHalf-life, t1/2 = 64 hoursNumber of half-lives, n = t / t1/2 = 168 hours / 64 hours = 2.625Activity at the start of the treatment is given byActivity = A0 = m / (M × t1/2)Where, M = molar mass of the Yittrium-90 M = 90 gm/molActivity = A0 = 2.5 / (90 × 64 × 2.303) Ci = 0.00010175 Ci = 10.175 mCi ≈ 10.2 mCic)Activity of Yittrium-90 after 1 weekThe time duration of 1 week = 7 × 24 hours = 168 hoursThe initial activity of the Yittrium-90 at the start of treatment, A0 = 10.2 mCiThe half-life of Yittrium-90 decay by beta emission is 64 hours.Number of half-lives after 1 week is:n = t / t1/2 = 168 hours / 64 hours = 2.625The activity after 1 week = A0 / 2n = 10.2 / (2^2.625) mCi = 2.05 mCiThe activity of the radioactive isotope after 1 week of treatment is less than 50 Ci. Hence, the treatment dosage will not be effective for 1 week. Therefore, the treatment dosage is not effective for a week.

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Han purple and Han blue are artificial barium copper silicate pigments that were created in China and utilized in ancient and imperial China beginning in the Western Zhou dynasty. They are also known as Chinese purple and Chinese blue. Chemists understand Chinese purple. The correct option is A.

Chemists create new, previously undiscovered substances as well as those that are naturally existing. Chemists research the characteristics of both organic and inorganic compounds. With the help of this knowledge, scientists can discover strategies to change certain compounds in order to make them more helpful.

Chemists carry out experiments in labs to analyze substances, create new goods, or enhance ones that already exist. They could focus on one or more fields, such as biochemistry, inorganic chemistry, or organic chemistry.

Thus the correct option is A.

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The correct phrase that describes the effect of adding a catalyst to a chemical reaction in order to increase the reaction rate is: (b) provides a different reaction pathway with a lower activation energy.

A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It achieves this by providing an alternative reaction pathway with a lower activation energy, making it easier for the reactant molecules to reach the transition state and proceed to form the products.

The catalyst itself is not permanently altered or consumed in the reaction and can participate in multiple reaction cycles, thereby increasing the overall reaction rate.

Overall, the presence of a catalyst alters the reaction kinetics by providing a different reaction pathway with a lower activation energy, resulting in an increased reaction rate.

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Answer:

(a)  The unit cell edge length 0.421 nm

Explanation:

Lets calculate -:

Given -

density = [tex]3.58g/cm^3[/tex]

Molecular weight of MgO = 24.31 +16

                                           [tex]40.13 g/mole[/tex]

Avagadro number = [tex]6.022\times10^2^3[/tex]

In rock salt structure , there are four anions and four cations , hence Z=4 (Number of formula per unit cell)

Now, using the formula -

                     [tex]d=\frac{ZM}{N_Aa^3}[/tex]

               [tex]a=[\frac{ZM}{N_Ad}]]^\frac{1}{3}[/tex]

Now, putting the given values

   [tex]a=\frac{4\times40.13g/mole}{6.022\times10^2^3\times(3.58g/cm^3)}[/tex]

  [tex]4.21\times10^-^8 cm[/tex]

  = 0.421 nm

Hence , the unit cell edge length = 0.421 nm

The unit cell edge length of magnesium oxide (MgO) is equal to 0.421 nanometer.

Given the following data:

Scientific data:

To determine the unit cell edge length:

Mathematically, the unit cell edge length for a face-centered cubic (FCC) structure is given by the formula:

[tex]a=\sqrt[3]{\frac{ZM}{\rho N_A} }[/tex]

Where:

Substituting the given parameters into the formula, we have;

[tex]a=\sqrt[3]{\frac{4 \; \times \;40.31}{3.58\; \times \;6.02 \times 10^{23}} }\\\\a=\sqrt[3]{\frac{161.24}{2.16 \times 10^{24}}}\\\\a=\sqrt[3]{7.47 \times 10^{-23}} \\\\a=4.21 \times 10^{-8}\;meter[/tex]

Note: [tex]1 \;nanometer = 1 \times 10^{-9} \;meter[/tex]

a = 0.421 nanometer.

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Answer:

50 kJ

Explanation:

Activation energy is between the energy of reactants and the peak of the curve.

200 kJ - 150 kJ = 50 kJ

The correct answer is 50kJ

Hence 50KJ is activation energy

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The overall order of the reaction is 2.5.

The reaction rate will not change if A is doubled,

We add together the individual orders of the reactants to get the reaction's overall order.

We have the following when the reaction has zero order in A, half order in B, and second order in C:

Order as a whole: 0 + 1/2 + 2 = 2 1/2 or 2.5

As a result, the reaction's overall order is 2.5.

We must comprehend how the response rate varies with the concentration of A in order to calculate the factor by which the rate changes when A is doubled. Doubling the concentration of A won't change the reaction's pace because the reaction is zero order in A.

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The molecularity of Step 1: CI(g) + O3(g) ⟶ CIO(g) + O2(g) is bimolecular.What is molecularity?Molecularity refers to the number of reactant particles that are involved in a step in a chemical reaction.

The total number of molecules reacting in an elementary reaction is called its molecularity. For instance, if two atoms combine to create a molecule, the reaction is known as a bimolecular reaction.The proposed mechanism for the decomposition of ozone in the stratosphere is Step 1: CI (g) + O3 (g) ⟶ CIO (g) + O2 (g) Step 2: CIO (g) + O3 (g) ⟶ CI (g) + 2O2 (g)Let's calculate the molecularity of Step 1:We can see that one Cl atom and one O3 molecule combine to produce one CIO molecule and one O2 molecule. The rate law is thus dependent on the concentration of both reactants. Therefore, the molecularity of Step 1 is bimolecular.

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By performing the necessary calculations for each case, we can determine the pH values for (a), (b), (c), (d), and (e) in the titration of HClO with KOH.

(a) Before the addition of any KOH, the solution contains only HClO. To calculate the pH, we need to consider the ionization of HClO. HClO is a weak acid, and its ionization can be determined using its ionization constant. By using the ionization constant and the initial concentration of HClO, we can calculate the concentration of H+ ions and convert it to pH.

(b) After adding 25.0 mL of KOH, a neutralization reaction occurs between HClO and KOH. The moles of HClO and KOH are now equal, and the solution contains the resulting salt. We can determine the concentration of OH- ions based on the amount of KOH added and calculate the pOH. From pOH, we can obtain the pH by subtracting it from 14.

(c) After adding 35.0 mL of KOH, the solution is still in excess of HClO. We need to determine the remaining moles of HClO and the resulting concentration of H+ ions to calculate the pH.

(d) After adding 50.0 mL of KOH, the moles of HClO and KOH become equal. The solution contains only the salt resulting from the neutralization reaction. We can calculate the concentration of OH- ions and convert it to pOH and then pH.

(e) After adding 60.0 mL of KOH, the solution is in excess of KOH. We need to determine the excess moles of KOH and calculate the concentration of OH- ions to obtain the pOH and pH.

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The required correct answer is  Nitrogen

Explanation: The following elements is a nonmetal: Nitrogen.

Elements are pure substances that cannot be split into simpler substances through chemical methods. The chemical elements are arranged in the periodic table according to their atomic number, electron configurations, and chemical properties. Elements can be classified into three categories: metals, nonmetals, and metalloids.

Nitrogen is a nonmetal element. Nitrogen is a non-metallic chemical element that is a colorless, odorless, and tasteless gas that makes up the majority of Earth's atmosphere. Nitrogen has an atomic number of 7 and is designated by the symbol N.

The element nitrogen has a wide range of uses, including in fertilizers, explosives, rocket fuel, and organic chemistry, among other fields. Nitrogen is also used to preserve and package food products because it is an inert gas that does not react with most other compounds.

To summarize, Nitrogen is a nonmetal element. It is a colorless, odorless, and tasteless gas that makes up the majority of Earth's atmosphere. Nitrogen is used for a variety of purposes, including fertilizers, explosives, rocket fuel, and organic chemistry, among others.

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Answer:

somebody answer this please>>>!!!

Explanation:

!!!

Answer:

1.35 moles of CaCO₃

Explanation:

Molarity, it is a sort of concentration that indicates the amount of moles in 1 L of solution.

M = mol /L

This is a simple equation

M = 2.25 M

Our volume is 0.6L

M . L = mol

Then, 2.25 mol/L . 0.6L = 1.35 moles

We need 1.35 moles of CaCO₃

Answer:

False

Explanation:

Scientifically, energy can never be created or destroyed. However it can be transfered. This law is called The Law of Conservation of Energy.

The reactions are expected to occur spontaneously in the forward direction;  Fe²⁺ + Cu²⁺ → Fe³⁺ + Cu, Zn + Pb²⁺ → Zn²⁺ + Pb, Cl₂ + 2Na → 2NaCl, and Mg + 2HCl → MgCl₂ + H₂. Option A, B, D, and E are correct.

To determine which of the redox reactions are expected to occur spontaneously in forward direction, we will compare the standard reduction potentials of the involved species.

Fe²⁺ + Cu²⁺ → Fe³⁺ + Cu

For this reaction, the reduction potential of Fe²⁺ (-0.44 V) is lower than that of Cu²⁺ (+0.34 V). Therefore, the reaction will be expected to occur spontaneously in the forward direction.

Zn + Pb²⁺ → Zn²⁺ + Pb

The reduction potential of Zn (-0.76 V) is lower than that of Pb²⁺ (-0.13 V). Therefore, the reaction will be expected to occur spontaneously in the forward direction.

Ag⁺ + Na → Ag + Na⁺

The reduction potential of Ag⁺ (+0.80 V) is higher than that of Na (approximately -2.71 V). Therefore, the reaction is not expected to occur spontaneously in the forward direction.

Cl₂ + 2Na → 2NaCl

The reduction potential of Cl₂ (+1.36 V) is higher than that of Na (approximately -2.71 V). Therefore, the reaction is expected to occur spontaneously in the forward direction.

Mg + 2HCl → MgCl₂ + H₂

The reduction potential of Mg (-2.37 V) is lower than that of H⁺ (0 V). Therefore, the reaction is expected to occur spontaneously in the forward direction.

Based on the comparison of reduction potentials, the following reactions are expected to occur spontaneously in the forward direction;

Fe²⁺ + Cu²⁺ → Fe³⁺ + Cu

Zn + Pb²⁺ → Zn²⁺ + Pb

Cl₂ + 2Na → 2NaCl

Mg + 2HCl → MgCl₂ + H₂

Hence, A. B. D. E. is the correct option.

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Answer: Basic

Explanation:

A solution with a pH of more than 7 is considered basic.

Answer:

DNA

Explanation:

The eukaryotic cell participates in the formation of complex organisms and contains a nucleus, cytoplasmic organelles, and a cytoskeleton.

The answer should be DNA based on the wording of the question. Hopefully this helped a little bit.

Yes, the resulting solution is a buffer solution. The pH of the resulting solution is 3.35. The change in pH due to the addition of 0.05 moles of sodium hydroxide is a decrease of 0.70 units, resulting in a new pH of 2.65.

Yes, the resulting solution is a buffer solution. A buffer solution is a solution that can resist changes in pH when small amounts of acid or base are added to it. In this case, the nitrous acid and sodium hydroxide react to form their conjugate acid-base pair, which can help maintain the pH of the solution.

To determine the pH of the resulting solution, we need to compare the concentrations of the conjugate acid (nitrous acid, HNO₂) and conjugate base (nitrite ion, NO₂⁻) in the buffer solution.

The Henderson-Hasselbalch equation is used to calculate the pH of a buffer solution

pH = pKa + log([conjugate base]/[conjugate acid])

Volume of nitrous acid (conjugate acid) = 250 mL = 0.250 L

Concentration of nitrous acid (conjugate acid) = 1.00 M

Volume of sodium hydroxide (conjugate base) = 50 mL = 0.050 L

Concentration of sodium hydroxide (conjugate base) = 1.00 M

pKa of nitrous acid = 3.35

[conjugate base] = concentration of sodium hydroxide = 1.00 M

[conjugate acid] = concentration of nitrous acid = 1.00 M

pH = 3.35 + log(1.00/1.00) = 3.35

Therefore, the pH of the resulting solution is 3.35.

For the second part of the question, if an additional 0.05 moles of sodium hydroxide are added, we need to determine the change in pH.

Since the volume of the solution remains the same, the final concentration of sodium hydroxide ([conjugate base]) will be

[conjugate base] = (initial moles of sodium hydroxide + additional moles of sodium hydroxide) / total volume

[conjugate base] = (0.050 moles + 0.05 moles) / (0.250 L + 0.050 L) = 0.20 M

Using the Henderson-Hasselbalch equation with the updated concentration of the conjugate base, we can calculate the new pH

pH = pKa + log([conjugate base]/[conjugate acid])

pH = 3.35 + log(0.20/1.00) = 3.35 - 0.699 = 2.65

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Answer:

Circulatory

Explanation:

The circulatory system consists of the heart, lungs, arteries, veins, coronary, and portal vessels.

The pH values at various volumes of acid (HCl) added to the dibasic compound B can be determined based on its pKb values. By calculating the concentration of the species present at each volume, the Henderson-Hasselbalch equation can be used to find the corresponding pH values. A graph of pH versus the volume of acid added can be plotted using these calculations.

To find the pH at each volume of acid added, we need to consider the dissociation of the dibasic compound B and the resulting concentrations of its species. The pKb1 and pKb2 values indicate the equilibrium constants for the dissociation reactions. Initially, the volume of acid added is 0 mL, and the concentration of B is 0.100 M. At this point, B is fully ionized, and its concentration is 0 M. Therefore, the pH can be determined by calculating the concentration of OH- ions using the pKb2 value.

As acid (HCl) is added, it reacts with the B species. At each volume, the concentration of B, BH+, and BH2+ can be calculated based on the initial concentration and the volume of acid added. By applying the Henderson-Hasselbalch equation (pH = pKa + log([A-]/[HA])), the pH can be determined using the appropriate pKb value for each species. By repeating these calculations for each volume of acid added (1, 5, 9, 10, 11, 15, 19, 20, and 22 mL), the corresponding pH values can be obtained. These pH values can then be plotted against the volume of acid added to create a graph of pH versus Va.

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Answer:

chlorine

Explanation:

Answer: D: sun

Explanation:

Answer:

this is hard

Explanation:

Answer:

I'm not sure but maybe 1 g ?!

Answer:

He could add a model of soil layers.

Explanation: C

In an ecosystem where water from mine is polluting river it can be tested by building a model of the soil layers and test if water passes through any of them.

Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.

Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.

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Answer:

It works in most daily situations.

Explanation:

:)

Answer:

C. It works in most daily situations.

Explanation:

Edge-nuity 2022

Answer:

if you will decrease the HCO3- so the less H+ ion will be form and reaction will more likely shift to product and when HCO3- decreases pH value increases and vica versa for the increasing HCO3 the more H+ ion will be form and reaction will shift to product and the pH value will decreases!!

I've doubt in reaction shift coz whatever is the amount of HCO3- this is completely gonna form number of H+ so reaction shift may or may not be same!!

The balanced chemical equation is given as

MnO₄⁻(aq) + As₄O₆(s) + 7H₂O(l) → Mn²⁺(aq) + AsO₄³⁻(g) + 14H⁺(aq) + 5e⁻

The coefficient of water (H₂O) is 7.

To balance the equation in acidic solution:

MnO₄⁻(aq) + As₄O₆(s) → Mn²⁺(aq) + AsO₄³⁻(g)

We can balance the atoms one by one:

Balance the atoms other than oxygen and hydrogen:

MnO₄⁻(aq) + As₄O₆(s) → Mn²⁺(aq) + AsO₄³⁻(g)

Balance oxygen atoms by adding H₂O:

MnO₄⁻(aq) + As₄O₆(s) + 7H₂O(l) → Mn²⁺(aq) + AsO₄³⁻(g)

Balance hydrogen atoms by adding H⁺ ions:

MnO₄⁻(aq) + As₄O₆(s) + 7H₂O(l) → Mn²⁺(aq) + AsO₄³⁻(g) + 14H⁺(aq)

Balance the charge by adding electrons (e⁻):

MnO₄⁻(aq) + As₄O₆(s) + 7H₂O(l) → Mn²⁺(aq) + AsO₄³⁻(g) + 14H⁺(aq) + 5e⁻

Now the equation is balanced. The coefficient of water (H₂O) is 7.

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Answer:

Li⁺(aq) + 2Br⁻(aq) + Pb²⁺(aq) + NO₃⁻(aq) → PbBr₂(s) + NO₃⁻(aq) + Li⁺(aq)

A precipitate forms

Explanation:

To solve this question we must know the general solubility rules:

All group 1A (Li, Na, K...) and NH₄⁺ ions are always soluble.

The nitrates (NO₃⁻) and acetates are always solubles.

Cl⁻, Br⁻ and I⁻ are soluble except in the presence of Ag⁺, Pb²⁺, Cu⁺ and Hg₂²⁺

That means in the mixture of ions that we have, the Br⁻ will react with Pb²⁺ to produce PbBr₂(s):