how many molecules are there in 9.34 grams of water

The half-life of an element that decays by 3.415% each day is approximately 20.27 days.

The half-life of an element can be calculated using the formula:

half-life = (ln(2)) / (decay constant)

where the decay constant is the rate at which the element decays per time period. In this case, the element decays by 3.415% each day. To find the decay constant, we convert the percentage to a decimal by dividing it by 100:

decay constant = 0.03415

Now we can calculate the half-life:

half-life = (ln(2)) / (0.03415)

A calculator can be used to find the value of ln(2), which is approximately 0.693:

half-life = 0.693 / 0.03415 = 20.27 days

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Final answer:

To make 150.0 mL of a 1.70 M KBr solution, you need 30.33 grams of KBr. This is calculated by multiplying the molarity (1.70 M), the volume in liters (0.150 L), and the molar mass of KBr (119.00 g/mol).

Explanation:

To calculate the mass of KBr needed to make 150.0 mL of a 1.70 M solution, we need to use the formula:

Mass (g) = Molarity (M) × Volume (L) × Molar Mass (g/mol)

First, convert the volume from milliliters to liters by dividing by 1000:

150.0 mL = 0.150 L

Next, find the molar mass of KBr, which is the sum of the atomic masses of potassium (K) and bromine (Br). Potassium has an atomic mass of 39.10 g/mol, and bromine has an atomic mass of 79.90 g/mol:

Molar Mass of KBr = 39.10 g/mol + 79.90 g/mol = 119.00 g/mol

Now, we can calculate the mass of KBr:

Mass of KBr = 1.70 M × 0.150 L × 119.00 g/mol = 30.33 grams

Therefore, you should use 30.33 grams of KBr to make the solution.

The equilibrium associated with [tex]\text{K}_{a3}[/tex] for [tex]\text{H}_3\text{PO}_4[/tex] is as follows:

 [tex]\boxed{\text{HPO}^{2-}_{4}(aq)+\text{H}_{2}\text{O}(l)_{\rightleftharpoons}^{{K}_{a3}}\text{PO}^{3-}_{4}(aq)+\text{H}_{3}\text{O}^{+}(aq)}[/tex]

Further Explanation:

Acids are substances that can donate hydrogen ion [tex]\text{H}^{+}[/tex] or proton in their aqueous solutions.

Classification of acids:

1. Monoprotic acids

Acids that are capable to donate single proton in solutions are monoprotic acids. For example, HCl is a monoprotic acid due to its tendency to donate only one proton in solutions.

2. Polyprotic acids

Acids that are capable to donate more than one proton in aqueous solutions are called polyprotic acids. For example, [tex]\text{H}_2\text{SO}_4[/tex] and [tex]\text{H}_3\text{PO}_4[/tex] are all polyprotic acids.

Acid strength is measured with the help of dissociation constant. Itis denoted by [tex]\text{K}_a[/tex]. Since [tex]\text{H}_3\text{PO}_4[/tex] contains three hydrogens in it, it can donate three hydrogen ions in solutions so it is triprotic acid.

Dissociation of [tex]\text{H}_3\text{PO}_4[/tex] occurs as follows:

[tex]\begin{aligned}\text{H}_3\text{PO}_4(aq)+\text{H}_2\text{O}(l)_{\rightleftharpoons}^{K_{a1}}\text{H}_2\text{PO}^{-}_{4}(aq)+\text{H}_3\text{O}^{+}(aq)\\\text{H}_2\text{PO}^{-}_{4}(aq)\text{H}_2\text{O}(l)_{\rightleftharpoons}^{K_{a3}}\text{HPO}^{2-}_{4}(aq)+\text{H}_{3}\text{O}^{+}(aq)\\\text{HPO}^{2-}_{4}(aq)+\text{H}_{2}\text{O}(l)_{\rightleftharpoons}^{K_{a3}}\text{PO}^{3-}_{4}(aq)+\text{H}_{3}\text{O}^{+}(aq)\end{aligned}[/tex]  

Where,

[tex]{{\text{k}}_{{\text{a1}}}}[/tex] is the first dissociation constant of [tex]{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}}[/tex].

[tex]{{\text{k}}_{{\text{a2}}}}[/tex] is the second dissociation constant of [tex]{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}}[/tex].

[tex]{{\text{k}}_{{\text{a3}}}}[/tex] is the third dissociation constant of [tex]{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}}[/tex].

The expression of [tex]{{\text{k}}_{{\text{a3}}}}[/tex] for [tex]{{\text{H}}_{\text{3}}}{\text{P}}{{\text{O}}_{\text{4}}}[/tex] is as follows:

[tex]{{\text{k}}_{{\text{a3}}}} = \dfrac{{\left[ {{\text{PO}}_4^{3 - }} \right]\left[ {{{\text{H}}_{\text{3}}}{{\text{O}}^ + }} \right]}}{{\left[ {{\text{HPO}}_4^{2 - }} \right]}}[/tex]  

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Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Equilibrium

Keywords: acids, monoprotic acid, polyprotic acid, hydrogen ions, ka3, H3PO4, acid strength, dissociation constant, first dissociation constant, second dissociation constant, third dissociation constant.

Answer:

C. IT FLOWS THROUGH VENEZUELA

Explanation:

correct asnwer

The gas that is having lowest density will diffuse faster than other gases. As lesser denser will diffuse more quickly than the one which is more denser. Density is directly proportional to mass of the substance that is more mass of the substance is , more denser it will be. So here the Gas A is having lesser molecular weight than the other gases so it will diffuse more quickly than the other gases.

Gas A; MW = 14.28 g/mol

Answer: Mass of the substance is 1.792 kg

Explanation: Density of a substance is defined as the mass contained per unit volume.

[tex]Density=\frac{mass}{volume}[/tex]

Given:

Volume = 560 ml

Density = 3.2 g/ml

[tex]Mass=Density\times volume[/tex]

[tex]Mass=3.2g/ml\times 560ml=1792g[/tex]

Mass of the substance is 1792 g or 1.792 kg.

 the answer is combustion

The given equation represents a combustion reaction. The organic gas combines with atmospheric oxygen to form carbon dioxide and water .

Combustion is a type of reaction, in  which gaseous reactants combines with atmospheric oxygen to form carbon dioxide and water. In combustion reaction heat energy is released by the reaction system.

The reaction from which a heat energy is released is called an exothermic reaction. Thus, combustion is an exothermic reaction. The reaction in which heat is absorbed the system is called endothermic reaction.

In the given reaction, 2 moles of propanol reacts with 9 moles of oxygen forming 6 moles of carbon dioxide and 8 moles of water. This reaction is an example of combustion.

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Answer: Option (b) is the correct answer.

Explanation:

When copper wire is place into the atmosphere or anywhere then there is possibility that some oxide layer or impurity must have deposited over its surface.

So, when we sanded copper wire then these impurities get removed and copper metal gets exposed onto the surface.

Thus, we can conclude that you sanded the copper wire before burning it to make sure that copper metal was exposed on the surface of the wire.

Answer:

B. to make sure that copper metal was exposed on the surface of the wire

Explanation:

Right on Edgen.

Answer: D

Explanation:

Option D: 5

IMA is Ideal Mechanical advantage, for pulley system it is equal to the number of ropes present in the system. At ideal conditions, it is equal to the number of times, input force is getting multiplied. For example, If a pulley uses two ropes, its required mechanical force to displace the load will be divided into two or the distance that should be pulled will be multiplied by two (keeping total energy constant).

In the pulley system in diagram, there are total of 5 ropes in the system that is total strand that lead directly to the load thus, IMA for this pulley system will be 5.

Final answer:

The potential first-order rate law is rate = k[A] or rate = k[B], and the potential second-order rate law is rate = k[A][B].

Explanation:

The potential first-order rate law for the given reaction aA + bB → cC + dD is rate = k[A] or rate = k[B]. This means that the rate of the reaction is directly proportional to the concentration of either reactant A or reactant B.

The potential second-order rate law for the given reaction is rate = k[A][B]. This indicates that the rate of the reaction depends on the product of the concentrations of both reactant A and reactant B.

The element that would be a positive ion in a compound between Sr and Te would be Sr.

Elements form positive or negative ions based on the number of valence electrons their atoms contain and the tendency to either donate these electrons to form bonds or accept more electrons to form bonds.

The donation of acceptance of electrons will enable atoms to form an octet structure.

The number of valence electrons in Sr atoms is 2. In order to form an octet when bonding, these 2 electrons are readily donated rather than accepting more electrons. Thus, Sr ions are usually [tex]Sr^{2+[/tex].

The number of valence electrons in Te atoms is 6. Hence, instead of donating these electrons to form an octet, it will rather accept 2 more electrons. Thus, Te ions are usually [tex]Te^2^-[/tex].

In other words, Sr would be the positive ion in a compound.

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Final answer:

Strontium (Sr) would form a positive ion in a compound since it is an alkaline earth metal that readily loses electrons to become a cation, whereas tellurium (Te) tends to gain electrons to form an anion.

Explanation:

Between the elements strontium (Sr) and tellurium (Te), Sr would typically form a positive ion in a compound. This is because Sr is an alkaline earth metal and is found in Group 2 of the periodic table, where elements readily lose electrons to form cations with a +2 charge. On the other hand, Te is a metalloid in Group 16, known for gaining electrons to form anions with a -2 charge. Compounds are neutral, which means that the total number of positive charges must balance the total number of negative charges.

Additionally, Sr is lower down in its group than Ca, making it easier to remove an electron from Sr than from Ca. Hence, Ca has the higher ionization energy (IE) compared to Sr. When considering a potassium ion (K+), it would also be harder to remove an electron because it already has a positive charge. Therefore, the IE of K+ is significantly higher, especially since the next electron to be removed would come from a different electron shell.

The answer is plastic...

Hope this helps.

Answer:

true

Explanation:

Explanation:

Molar heat combustion:

Molar heat of combustion is defined as heat released when 1 mole of substance is burnt under the action of oxygen gas to give water and carbon-dioxide.It is measured in kiloJoules (kJ) per mole.This heat of energy can be positive or negative.

The molar heat of combustion is illustrated as the heat discharged when one mole of the component is burnt by reacting with oxygen gas to provide carbon dioxide and water. It is determined in kJ per mole. This heat of energy can be negative or positive. In case if the enthalpy is negative than the reaction is considered as an exothermic reaction, and if the enthalpy is positive than the reaction is considered as an endothermic reaction.

Final answer:

Coastal areas like Maryland have milder climates due to the moderation by nearby ocean water, which has a stable temperature that influences the air temperature over land. In contrast, inland areas such as Kansas and Iowa experience more extreme temperatures due to their distance from the ocean's moderating effects and greater influence from continental air masses.

Explanation:

The location of an area relative to the coast significantly influences its climate due to the effects of oceanality and continentality. Coastal Maryland, being near the Atlantic Ocean, experiences milder conditions because the temperature of ocean water remains relatively stable throughout the year, moderating the air temperature over the land. In contrast, inland areas such as Kansas and Iowa are subject to more extreme temperatures due to their distance from the ocean's moderating influence, leading to significantly warmer summers and colder winters.

Ocean water has a high heat capacity, which means it absorbs and releases heat more slowly than land, resulting in a smaller range of temperature fluctuations. This heat inertia is why coastal areas tend to have more moderated climates. For example, airflow from the ocean keeps San Francisco's climate mild and more constant throughout the year, while Salt Lake City, which is an inland city at approximately the same latitude, experiences greater temperature variation.

In summary, coastal regions are influenced by the temperature of the nearby ocean, which changes little with the seasons. This results in a milder climate with less variation between summer and winter temperatures. Conversely, inland regions are more subject to continental air masses, leading to a larger range in temperatures and more extreme seasonal conditions.

Answer:

people walking on the sidewalk crush the calcium chloride pellets.

Explanation:

When calcium chloride pellets are crushed with feet it increases the surface area of the calcium chloride. As the surface area increase the number of collision between the reactant molecules increases. Here the reactant molecules are calcium chloride ions and water molecules. In the process of dissolution the calcium chloride ions get hydrated by the dipoles of the water molecules. As the frequency of collision increases it lowers the activation energy or threshold barriers to start a reaction.  

Final answer:

After two half-lives of 5,000 years each, only 25% of the original radioactive isotope would remain.

Explanation:

If the half-life of a radioactive isotope is 5,000 years, after 10,000 years, two half-lives will have passed. According to exponential decay, after the first half-life, 50% of the original isotope remains. After the second half-life, another half of this remaining amount will have decayed, leaving only 25% of the original isotope. We can use the expression (1/2)n, where 'n' is the number of half-lives, to calculate the remaining amount of the isotope. In this case, it would be (1/2)2 = 1/4 or 25%.