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Answer:

Half-life = 2.7 days

Explanation:

The radioactive decay of an isotope follows the equation:

Ln[A] = -kt + ln[A]₀

Where [A] could be taken as the amount of A after t time, k is decay constant, [A]₀ initial amount of A.

Replacing to solve k:

Ln[3.125g] = -k*13.5days + ln[100g]

-3.465736 = -k*13.5days

k = 0.2567days⁻¹

Half-life is:

half-life = ln2 / k

Answer:

Periodic Table

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Explanation:

The periodic table allows you to compare the elements and understand their properties​.

Periodic table is a tabular arrangement of elements in the form of a table. In the periodic table, elements are arranged according to the modern periodic law which states that the properties of elements are a periodic function of their atomic numbers.

It is called as periodic because properties repeat after regular intervals of atomic numbers . It is a tabular arrangement consisting of seven horizontal rows called periods and eighteen vertical columns called groups.

Elements present in the same group have same number of valence electrons and hence have similar properties while elements present in the same period show gradual variation in properties due to addition of one electron for each successive element in a period.

Learn more about periodic table,here:

https://brainly.com/question/11155928

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Explanation:

Beryllium has the highest Ionization energy

Answer:

3)alpha decay because alpha particles have two protons and two neutrons

Explanation:

When a radioactive isotope undergoes a decay, a daughter nucleus or nuclei is/are formed. The mass number and atomic number of the daughter nucleus gives us an idea of the nature of radioactive decay that the parent nucleus underwent.

If the daughter mass number of the daughter nucleus is four units less than that of the parent nucleus and the atomic  number of the daughter nucleus is two units less than that of the parent, then such a decay is an alpha decay.

An alpha particle has two protons and two neutrons thus it has a mass number of 4 and an atomic number of two.

Answer:reflection

Explanation:

Answer:

(a) The inverse relationship of Boyle's law.

Explanation:

A Cartesian diver is used in scientific experiments to demonstrate the certain principles in science such as;

i. The principle of floatation or the Archimedes' principle.

ii. The implication of the ideal gas law as seen in, for example, Boyle's law and pressure law,

iii. Pascal's principle.

The diver demonstrates that given a large soft drink bottle containing water and a medicine dropper at its top, squeezing the bottle pushes the dropper down to the bottom. When the squeezing stops, the dropper comes back to the top again.

Now using this to demonstrate Boyle's law (which shows the relationship between pressure and volume where increase in one results in the decrease in the other), when the bottle is squeezed (which means pressure is increased on the bottle), the water is forced into the medicine dropper thereby decreasing the volume of air in the dropper. Removing pressure on the bottle produces an opposite effect.

Answer:

The molecular weight of CO is 28.01g/mole.

Answer:

1.5 moles of KMnO4 will be produced from 1.5 moles of MnO2

Explanation:

The balanced equation of this chemical reaction is

2 MnO2 + 4 KOH + O2 → 2 KMnO4 + 2 KOH + H2

2 moles of MnO2 produces 2 moles of   KMnO4

That means 1 moles of KMnO4 will be produced from 1 moles of MnO2

Hence, 1.5 moles of KMnO4 will be produced from 1.5 moles of MnO2

The moles of manganese oxide were used in the reaction is 1.5 moles.

Stoichiometry of any reaction tells about the relative amount of species present before and after the chemical reaction.

Given chemical reaction is:

2MnO₂ + 4KOH + O₂ → 2KMnO₄ + 2KOH + H₂

From the stoichiometry of the reaction, it is clear that same moles of manganese oxide and potassium permanganate is involved in the reaction.

2 moles of KMnO₄ = produce by 2 moles of MnO₂

1.5 moles of KMnO₄ = produce by 2/2×1.5=1.5 moles of MnO₂

Hence, required moles are 1.5 moles.

To know more about moles, visit the below link:

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Answer:

Diffusion in gases

Diffusion is driven by differences in concentration. When chemical substances such as perfume are let loose in a room, their particles mix with the particles of air. The particles of smelly gas are free to move quickly in all directions

Explanation:

hope this helps

Answer:

Step 1;

q = w = -0.52571 kJ, ΔS = 0.876 J/K

Step 2

q = 0, w = ΔU = -7.5 kJ, ΔH = -5.00574 kJ

Explanation:

The given parameters are;

[tex]P_i[/tex] = 100 N·m

[tex]T_i[/tex] = 327 K

[tex]P_f[/tex] = 90 N·m

Step 1

For isothermal expansion, we have;

ΔU = ΔH = 0

w = n·R·T·ln([tex]P_f[/tex]/[tex]P_i[/tex]) = 1 × 8.314 × 600.15 × ln(90/100) = -525.71

w ≈ -0.52571 kJ

At state 1, q = w = -0.52571 kJ

ΔS = -n·R·ln([tex]P_f[/tex]/[tex]P_i[/tex]) = -1 × 8.314 × ln(90/100) ≈ 0.876

ΔS ≈ 0.876 J/K

Step 2

q = 0 for adiabatic process

ΔU = 25×(27 - 327) = -7,500

w = ΔU = -7.5 kJ

ΔH = ΔU + n·R·ΔT

ΔH = -7,500 + 8.3142 × 300 = -5,005.74

ΔH = ΔU = -5.00574 kJ

Answer:

Approximately [tex]2.46\; \rm mol[/tex].

Explanation:

Make use of the molar mass data ([tex]M({\rm C_2H_2}) = 26.04\; \rm g \cdot mol^{-1}[/tex]) to calculate the number of moles of molecules in that [tex]64.0\; \rm g[/tex] of [tex]\rm C_2H_2[/tex]:

[tex]\begin{aligned}n({\rm C_2H_2}) &= \frac{m({\rm C_2H_2})}{M} \\ &= \frac{64.0\; \rm g}{26.04\; \rm g\cdot mol^{-1}}\approx 2.46\; \rm mol\end{aligned}[/tex].

Make sure that the equation for this reaction is balanced.

Coefficient of [tex]\rm C_2H_2[/tex] in this equation: [tex]2[/tex].

Coefficient of [tex]\rm H_2O[/tex] in this equation: [tex]2[/tex].

In other words, for every two moles of [tex]\rm C_2H_2[/tex] that this reaction consumes, two moles of [tex]\rm H_2O[/tex] would be produced.

Equivalently, for every mole of [tex]\rm C_2H_2[/tex] that this reaction consumes, one mole of [tex]\rm H_2O[/tex] would be produced.

Hence the ratio: [tex]\displaystyle \frac{n({\rm H_2O})}{n({\rm C_2H_2})} = \frac{2}{2} = 1[/tex].

Apply this ratio to find the number of moles of [tex]\rm H_2O[/tex] that this reaction would have produced:

[tex]\begin{aligned}n({\rm H_2O}) &= n({\rm C_2H_2}) \cdot \frac{n({\rm H_2O})}{n({\rm C_2H_2})} \\ &\approx 2.46\; \rm mol \times 1 = 2.46\; \rm mol\end{aligned}[/tex].

Answer:

the relationship between mass and volume

Answer:

x is HCl because pH = 2 (acid and it reacted with Mg plus it turned litmus paper to red)

y is NaOH because pH = 10 (base and turned litmus paper to blue)

z is NaCl because pH = 7 (neutral and no reaction to litmus paper and Mg)

Answer:

c

Explanation:

kw=h+bls

Hydroelectric energy is produced.

To balance Ca + Cl2 = CaCl2 you'll need to be sure to count all of atoms on each side of the chemical equation.

Once you know how many of each type of atom you can only change the coefficients (the numbers in front of atoms or compounds) to balance the equation for Calcium + Chlorine gas.

Answer:

if it is espresso(1 shot), the coffee content to be considered is: (77/44)*(10/3)= 5.833= 0.005833 grams

Explanation:

Answer:

Al + 2 KOH + 6 H 2O → 3 H 2 + 2 K[Al(OH) 4] This is a complexation reaction: K[Al(OH) 4] is the formed complex. ; Silvery-white, malleable, ductile, odorless metal.

Explanation:

I hope this help

Answer:

From Pressure Law

P1/T1 = P2/T2

Changing our temp to kelvin

T1 = 47 +273 = 320K

We're looking for T2

Making T2 the subject

T2 =P2 x T1 / P1

= 655 x 320/850

T2 = 246K

Answer:

pOH = 8.19

Acidic solution (pH < 7.0)

Explanation:

The pOH of the solution is defined as:

pOH = - log [OH⁻]

Since we have [OH⁻] = 6.5 x 10⁻⁹ M, we calculate the pOH as follows:

pOH = - log (6.5 x 10⁻⁹) = 8.19

To know if the solution is acidic, neutral or basic, we have to calculate the pH from the value of pOH:

pH + pOH = 14

⇒ pH = 14 - pOH = 14 - 8.19 = 5.81

The solution is acidic because pH < 7.0.

Answer:

[tex]98 \times x6x \geqslant {36461 { {3 \frac{ \sqrt[ |?| ]{?} }{?} }^{2} }^{?} }^{2} [/tex]

okay

Answer:

[tex]V_1=82.6mL[/tex]

Explanation:

Hello there!

In this case, according to this question, we will need to deal with this dilution problem, because it is asking for the volume of a 12.1-M stock solution of HCl. In such a way, we can use the following equation, under the assumption of no change in the number of moles in the solution:

[tex]M_2V_2=M_1V_1[/tex]

Thus, we solve for the initial volume, V1, as shown below:

[tex]V_1=\frac{M_2V_2}{M_1}[/tex]

And plug in the initial concentration and final concentration and volume to obtain:

[tex]V_1=\frac{2000mL*0.500M}{12.1M}\\\\V_1=82.6mL[/tex]

Regards!

Answer:

60g/mol.

Explanation:

TO FIND :-

FACTS TO KNOW BEFORE FINDING ANSWER :-

SOLUTION :-

Molar mass of C₃H₈O = 3(Molar mass of C) + 8(Molar mass of H) + 1(Molar mass of O)

⇒ Molar mass of C₃H₈O = (3×12) + (8×1) + 16 = 36 + 8 + 16 = 60g/mol.

Answer:

baking cookies

Explanation:

One example of using a scientific method is baking cookies. You make a hypothesis that you cookies will be done in 15 minutes. Then, after 15 minutes, you see that either your hypothesis was correct and you cookies are perfect or you need to bake them longer making you hypothesis incorrect. (please change the wording up a bit if you want. i tried to make it make the most sense)

Answer:

Explanation:

When you loose your phone. You try to remember where you last used your phone, and question yourself where you might have left it. If you say that you probably left it in the kitchen, that would be like your hypothesis. Then you go look for it where you thought you left it which would be your experiment. If maybe it is not there that would be like your conclusion so you would reject your hypothesis because it was wrong. Then you try the scientific method again but with a different hypothesis, like that maybe you left it in the living room. You do your experiment which is when you go look for it. In the conclusion if your hypothesis was right you accept your hypothesis. That can be an example of how we use the scientific method in our everyday lives.

Answer:

azufre

Explanation:

El azufre es un mal conductor del calor y aislante de la electricidad.

Answer:

9 moles of Sulphur will react with 6moles of Aluminum