what are three ways of measuring the amount of substance?

Answer:

B

Explanation:

Copper is lower on the activity series, so it can't replace nickel in this reaction. Therefore, no reaction will occur.

For a radioactive isotope has an activity of 9.60 mCi.  , the half-life of the isotope is mathematically given as

t0.5 = 23893 s

Generally, the equation for the half-life  is mathematically given as

t0.5=T*0.693

Where

A = A0 e^(-t/T)

t/T = lnA0/A

3.75 hours/T=ln 9.60/7.39

T = 34478.5 s

Therefore

t1/2 = TX0.693

t0.5 = 23893 s

In conclusion, the half life

t0.5 = 23893 s

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Answer:

galvanic cell or electrochemical cell

Explanation:

the electrolytic cell needs electric supply to make charges flow from anode to cathode while the galvanic cell doesn't.

The electrolytic cell needs electric supply to make charges flow from anode to cathode while the galvanic cell doesn't.

A device that can produce electrical energy from the chemical reactions taking place inside it is called an electrochemical cell. Electrochemical cells include a common 1.5V cell seen in TV remotes and clocks as well as lithium-ion batteries found in smart phones.

Galvanic cells, often referred to as Voltaic cells, and electrolytic cells are the two forms of electrochemical cells.

"In galvanic cells, spontaneous redox reactions take place, converting chemical energy into electrical energy. As opposed to electrolytic cells, which use an external power source to drive internal chemical reactions, which transform electrical energy into chemical energy.

Therefore, The electrolytic cell needs electric supply to make charges flow from anode to cathode while the galvanic cell doesn't.

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Answer:

many atoms are in 6.5 moles of zinc? 6.5 moles. 6.02 x 10. 23 atoms =.

3 pages

Explanation:

The number of atoms in the 6.5 moles of zinc is equal to 39.15 × 10²³ atoms of zinc.

A mole is a scientific unit that is used to measure a large number of quantities of molecules, ions, atoms, or other particular particles. The number of particles or atoms in a mole is the same for almost all substances.

The number of entities present in one mole was experimentally found to be equal to 6.023 × 10 ²³, which is a constant. This number is termed as Avogadro’s number or Avogadro’s constant.

Given, the number of moles of zinc = 6.5 moles

The number of atoms of zinc in one mole = 6.023 × 10 ²³

Then 6.5 moles of zinc will have atoms of zinc = 6.023 × 10 ²³ × 6.5

                                                                             =  39.15 × 10 ²³ atoms.

Therefore, the 39.15 × 10 ²³ Zinc atoms are in 6.5 moles of zinc.

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Some voltaic cells are called dry because they do not have liquids in them.

They are called dry because their electrolytes are usually in paste forms instead of aqueous form in which the electrolytes of wet cells are usually are.

The pastes in dry cells are made moist enough for the electric current to be able to flow through them.

Dry cells are advantageous because they are less heavy and one does not have to worry about the electrolyte spilling, unlike wet cells.

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Answer: 4

Explanation:

Then double displacement will happen

The reaction given by

[tex]\\ \rm\Rrightarrow Li_3AsO_4+Fe(NO_3)_3\longrightarrow LiNO_3+FeAsO_4[/tex]

Remember that nitrate ions and compounds are highly soluble in water like HNO_3 ,KNO_3.

So LiNO_3 remains dissolved in water or aqueous.

FeAsO_4 will be in solute form i.e precipitate

Answer:

Strong Alkali – Is an alkali which dissociates – almost completely in aqueous solution thereby producing a – high concentration of hydroxyl [OH– ] ions.

Weak alkali – Is an alkali which dissociates – only partially in aqueous solution thereby producing a – low concentration of hydroxyl [OH–] ions.

Answer:

B. a characteristic of a substance that can be measured or observed without changing the chemical identity of the substance

Explanation:

The definition of a physical property is " a property (as color, hardness, boiling point) of matter not involving in its manifestation a chemical change."

The only choice that matches this description fully is the second one, or B, so that is the answer.

hope this helps!

The structure of organic compounds allows them to function as pigments through chromophore and acid or basic groups.

This is defined as a colored substance which is completely or nearly insoluble in water.

The structure of organic compounds allows them to function as pigments include chromophore and the acid or basic groups such as OH, SO3H, etc.

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The mass in grams of the given beryllium sulfide is 99.2 g. The correct option is the second option - 99.2 g BeS

From the question, we are to determine the mass of the given beryllium sulfide.

From the given information,

Number of moles of beryllium sulfide (BeS) given = 2.42 moles

Using the formula,

Mass = Number of moles × Molar mass

Molar mass of BeS = 41 g/mol

Then,

Mass of BeS = 2.42 × 41

Mass of BeS = 99.22

Mass of BeS ≅ 99.2 g

Hence, the mass in grams of the given beryllium sulfide is 99.2 g. The correct option is the second option - 99.2 g BeS

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The concentration of the hydronium ion in hydrochloric acid is 0.0045 M, and the pH of the solution is 2.34.

pH is the potential of the hydrogen or the hydronium ions in the aqueous solution.

As the solution contains [tex]4.5 \times 10^{-3} \;\rm M\;[/tex] HCl the concentration of the hydronium ion will be the same, [tex]4.5 \times 10^{-3} \;\rm M.[/tex]

The pH of the solution is calculated as:

[tex]\begin{aligned} \rm pH &= \rm -log[H^{+}]\\\\&= - \rm log (4.5 \times 10^{-3})\\\\&= 2.34\end{aligned}[/tex]

The concentration of the hydroxide ion is calculated from pH and hydronium ion as:

[tex]\begin{aligned} \rm [H_{3}O^{+}][OH^{-}] &= 10^{-14}\\\\&= \dfrac{1 \times 10^{-14}}{4.5 \times 10^{-3}}\\\\&= 2.2 \times 10^{12}\end{aligned}[/tex]

Now, for the calcium hydroxide solution, the calculations are shown as,

[tex]\begin{aligned} \rm (H_3}\rm O^{+}) &= \rm antilog (-pH)\\\\&= \rm antilog (-8)\\\\&= 10^{-8} \;\rm M\end{aligned}[/tex]

pOH is calculated as:

[tex]\begin{aligned} \rm pOH &= 14- 8 = 6\\\\\rm [OH^{-}] &= \rm antilog (-6)\\\\&= 10^{-6} \end{aligned}[/tex]

The concentration of calcium hydroxide is calculated as:

[tex]\begin{aligned} &= \dfrac{1}{2} \times \rm [OH^{-}]\\\\&= 5 \times 10^{-4} \;\rm M\end{aligned}[/tex]

Therefore, the pH and the pOH give the concentration of the hydrogen or the hydronium ion and the hydroxide ion.

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Answer:

A mature leafy tree produces as much oxygen in a season as 10 people inhale in a year." "A 100-foot tree, 18 inches diameter at its base, produces 6,000 pounds of oxygen." "On average, one tree produces nearly 260 pounds of oxygen each year. Two mature trees can provide enough oxygen for a family of four.

Explanation:

hope this helps

The number of chlorine atoms present on the product side of the reaction is 6

Chemical equations are representations of chemical reactions using symbols and formula of the reactants and products.

The balancing of chemical equations follows the law of conservation of matter which states that matter can neither be created nor destroyed during a chemical reaction but can be transferred from one form to another.

2Al + 6HCl → 2AlCl₃ + 3H₂

Products => AlCl₃ and H₂

Number of Cl atoms = 2 × 3

Number of Cl atoms = 6 atoms

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Answer: 3. 6

Explanation: To put it simply

Answer:

Mixture

Explanation:

Air is a mixture, meaning it can be separated into its components without a chemical reaction taking place. In this case, it is a mixture of gases.

TLC means Thin Layer Chromatography. It is a method that can best be described as "Affinity-Based" used in the separation of compounds that are in a mixture.

Unreacted p-nitrobenzaldehyde is simply an organic aromatic compound that contains a nitro group para-substituted to an aldehyde. in this case, if it is unreacted, that means it is the same as before the chemical reation.

Note that the question is missing key information hence the general answer.

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Answer:

Biological Functions: processes and structures by which organisms adjust to short-term or long-term changes in their environment

If a spoon of copper metal is placed in a solution of ferrous sulfate then no reaction will take place.

Electrochemical series of metals is the series which gives idea about the reactivity of the metals if present in any solution of another metal.

Iron metal is placed at the top position with respect to the copper metal, means iron is more reactive than copper. So when a spoon of copper metal is placed in a solution of ferrous sulfate, copper will not able to displace the iron metals from its solution.

Hence no reaction will occur.

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Answer:

Intermolecular Forces: Review. Electronegativity is a measure of an atom's ability to attract the shared electrons of a covalent bond to itself. If atoms bonded together have the same electronegativity, the shared electrons will be equally shared.

Explanation:

hope this helped

Answer:

It is already balanced

Explanation:

hbr     +    khco3  ===>  h20 + kbr + co2     IS BALANCED

Answer:

1. Venus

471°C

2. Mercury

(430°C) during the day,  (-180°C) at night

3. Earth

16°C

4. Mars

-28°C

5. Jupiter

-108°C

6. Saturn

-138°C

7. Uranus

-195°C

8. Neptune

-201°C

Explanation:

.

Europeans wanted to trade things for rubber and oil with Africa

The indirect result of contaminants from commercial farming is algae.

Contaminant is a substance either chemical, physical that is very toxic or harmful to living organisms, when it is released into air, water, soil or food.

Contaminant are poisionus substance that are not deliberately or are deliberately introduced to space . This contaminants make things impure and they are highly poisionus.

Therefore, The indirect result of contaminants from commercial farming is algae.

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Answer:

58.6934

Explanation:

periodic table

Answer:

58.6934 u

Explanation:

You can find this from the atomic mass number on a Periodic Table, Nickel is 58.6934, therefore the mass of one atom of nickel is 58.6934 u.

Answer:

D = melting and vaporization

Explanation:

Pretend this is very cold ICE

A   heat the ice up to melting point

B  melt the ice to waterheat the water to boiling

D  change water to steam

E   heat the steam up (superheat the steam)

The equations obey the law of conservation of mass in that the number of moles of each component atom is balanced on both sides.

It states that mass is conserved during chemical reactions.

For the first equation: [tex]N_2(g) + 3H_2(g) --- > 2NH_3(g)[/tex], there are 2 nitrogen and 6 hydrogen atoms on the reactant and product's side respectively. Thus, the number of atoms is conserved.

For the second equation: [tex]HCI(aq) + KOH(aq) -- > KCI(aq) + H_2O (l)[/tex], there are an equal number of H, Cl, K, and O atoms at the reactant and product's sides. The number of atoms is also conserved.

Lastly in the equation: [tex]2Mg(s) + O_2(g) - 2MgO(s)[/tex], the number of each atom is also balanced on both sides.

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Answer:

200 kPa

(it is actually 199.999, but rounding up it is 200)

hope this helps!

Answer:

1500 Torr is  about 200 kPa

Answer:

measure the final temperature of water

0.14

Explanation:

I just needed to finish setting up my account