Radium has a half-life of 1500 years. How long will it take for 250kg of Radium to decay down to less than 10kg

above because its above

Answer:

NaOH is the limiting reactant.

Explanation:

Hello there!

In this case, according to the given information, it turns out firstly necessary to write out the chemical reaction between NaOH and HCl:

[tex]NaOH+HCl\rightarrow NaCl+H_2O[/tex]

Thus, since they react in a 1:1 mole ratio; we can now calculate the moles of each substance by using their volumes and molarities:

[tex]n_{NaOH}=0.0250L*0.81mol/L=0.02025molNaOH\\\\n_{HCl}=0.0650L*0.33mol/L=0.02145molHCl[/tex]

Now, since NaOH is in a fewer proportion, we infer just 0.02025 moles of HCl are consumed so that 0.0012 moles of this acid remain unreacted; in such a way, we infer that the NaOH is the limiting reactant for this reaction.

Regards!

Answer:

2Mg(s) + O2(g) ----->2MgO(s)

Explanation:

In writing a balanced chemical reaction equation, the rule of thumb is that the number of atoms of each element on the reactant side must be the same as the number of atoms of the same elements on the products side.

Hence for the reaction of magnesium and oxygen shown below;

2Mg(s) + O2(g) ----->2MgO(s)

We notice that there are two atoms each of magnesium and oxygen on both sides of the reaction equation hence the equation is balanced.

Answer:

The explanation according to the given question is summarized below.

Explanation:

Given:

Tris,

= 250 mM

Glycine,

= 1.92 M

According to the solution,

For the dilution pf 10X to 1X buffer, we get

= [tex]1 \ ml \ of \ 10X \ buffer +9 \ ml \ of \ distilled \ water[/tex]

= [tex]10[/tex]

i.e.,

⇒ [tex]10X \ to \ 1X=1:10 \ dilution[/tex]

Now,

⇒ [tex]10X (250 \ mM\ Tris \ HCl, 1.92M\ Glycine, and\ 1 \ percent (\frac{w}{v} ) SDS) ---->1X(25 \ mM \ Tris \ HCl,0.193 M\ Glycine, and \ 0.1 \ percent(\frac{w}{v} )SDS)[/tex]

Answer:

Explanation:

mass = 400 grams * [1 kg/1000 grams] = 0.400 kg

c = 387 Joules / (oC * kg)

Δt = 55 - 30 = 25 oC

E = m*c * Δt

E = 0.4 * 387 * 25

E = 3870 Joules

Answer:

See explanation and image attached

Explanation:

Hydrogen peroxide is made up of two atoms of hydrogen and two atoms of oxygen as shown in the image attached.

The two oxygen atoms are joined together by a single covalent bond and each of the oxygen atoms are bonded to one hydrogen atom each.

There are two lone pairs on each of the oxygen atoms.

The Lewis(dot) structure for hydrogen peroxide is shown in the image attached to this answer.

Answer:

Explanation:

Given the data in the question;

wavelength λ₁ = 853 nm = 853 × 10⁻⁹ m

wavelength λ₂ = 865 nm = 865 × 10⁻⁹ m

we determine the energy of each photons using the following expression;

[tex]E_{photon[/tex] = hc / λ

where h is Planck's constant ( 6.626 × 10⁻³⁴ J.s )

c is speed of light ( 3 × 10⁸ m/s )

For Photon with wavelength λ₁ = 853 × 10⁻⁹ m

[tex]E_{photon1[/tex] = hc / λ

we substitute

= ( ( 6.626 × 10⁻³⁴ J.s )( 3 × 10⁸ m/s ) ) / (853 × 10⁻⁹ m)

= 1.9878 × 10⁻²⁵ / 853 × 10⁻⁹

= 2.33 × 10⁻¹⁹ J

For Photon with wavelength  λ₂ = 865 × 10⁻⁹ m

[tex]E_{photon2[/tex] = ( ( 6.626 × 10⁻³⁴ J.s )( 3 × 10⁸ m/s ) ) / (865 × 10⁻⁹ m)

= 1.9878 × 10⁻²⁵ / 865 × 10⁻⁹

= 2.298 × 10⁻¹⁹ J

We know that; energy of the combined photon will be equal to the sum of energies of the two photons.

so

Energy of the combined photon = [tex]E_{photon1[/tex] + [tex]E_{photon2[/tex]

[tex]E_{combined[/tex] = 2.33 × 10⁻¹⁹ J + 2.298 × 10⁻¹⁹ J

[tex]E_{combined[/tex]  = 4.628 × 10⁻¹⁹ J

so wavelength of the new combined photon will be;

[tex]E_{combined[/tex] = hc / λ[tex]_{combined[/tex]

[tex]E_{combined[/tex]λ[tex]_{combined[/tex] = hc

λ[tex]_{combined[/tex] = hc / [tex]E_{combined[/tex]

we substitute

λ[tex]_{combined[/tex] = ( ( 6.626 × 10⁻³⁴ J.s )( 3 × 10⁸ m/s ) ) / 4.628 × 10⁻¹⁹ J

= 1.9878 × 10⁻²⁵ / 4.628 × 10⁻¹⁹

= 4.2952 × 10⁻⁷ m

= ( 4.2952 × 10⁻⁷ × 10⁹ )nm

= 429.5 nm

Therefore, Wavelength of the new 'combined' photon is 429.5 nm

[tex]\huge\mathsf{\red{\underline{\underline{Compound}}}}[/tex]

[tex]{\green{\dashrightarrow}}[/tex]A chemical compound is a chemical substance that is made of two or more atoms of different elements that share a chemical bond.

[tex]{\green{\dashrightarrow}}[/tex]A chemical formula represents the ratio of atoms per element that make up the chemical compound.

[tex]\large{\pink{\sf{5~ Examples~ of~ Compound~ are:-}}}[/tex]

Answer:

Explanation:

Short answer: Yes.

The coefficients may not be conserved, but mass always has to be. Take this equation as an example

2 Mg3P2 ===>   6Mg + P4

There is a 2 on the left side and 6 and 1 on the right. I hope you mean that the coefficient 2 is not equal to 7.

But let's look a little closer. You have to look at the molecular structure of the left and right side.

2Mg3P2 has 6 Mgs and 4 Ps on the left side.

6Mg is on the right. They are free standing.

P4    has 1 molecule consisting of 4 Ps.

Everything balances.

This is a terrific question to be asking. You need to understand the internal balance numbers vs the molecular ones on the out side.

That sounds like a bit of gobbledygook and it takes a bit of study.

2 Mg3P2 means that Mg3P2 is written twice.

Mg3P2 ==> "3 Mg2+   +  2P3+   and there is another one written the same way.

Mg3P2 ==> "3 Mg2+   +  2P3+  

Answer:

I think you forgot to post the question or picture

Answer:

How to Formulate an Effective Research Hypothesis

State the problem that you are trying to solve. Make sure that the hypothesis clearly defines the topic and the focus of the experiment.

Try to write the hypothesis as an if-then statement. ...

Define the variables.

Explanation:

Answer:

Explanation:

photosynthesis

the given chemical reaction is photosynthesis.

During photosynthesis carbon dioxide absorbed by plants reacts with water in presence of sunlight to give glucose and oxygen.

Answer:

non polar. polar ionic substance

Answer:

just look at what row the element is in. The lower the row, the bigger the radius

Explanation:

Answer:  the area of the telescope lens is \textit{0,08507 ft}

Explanation: Happy I could help!

Light energy travels in the form of waves.

Answer:

silicon

Explanation:

because silicon has 14 electrons and protons

Answer:

The correct answer is option 4, that is, there is exactly enough sodium carbonate.

Explanation:

Based on the given question, the reaction will be,

2 HCl (aq) + Na2CO3 (s) ⇒ 2 NaCl (aq) + CO2 (g) + H2O (l)

Therefore, for neutralizing 2 moles of HCl, one mole of Na2CO3 is required.

No of moles present in 1 Kg or 1000 grams of Na2CO3 will be,

Moles = Weight/Molecular mass of Na2CO3

Moles = 1000 / 106 = 9.43

Thus, 9.43 moles of Na2CO3 is present.

No of moles present in 1 liter of 9.75 M HCl is 9.75.

No. of moles present in 5 Liters of HCl (9.75 M),

= 5 × 9.75 = 48.75

Thus, for 2 moles of HCl 1 mole of Na2CO3 is required. Now for 48.75 moles of HCl, the moles required of Na2CO3 is 9.75. Therefore, for complete neutralization, the moles of Na2CO3 required is 9.75, and the present moles is 9.43.

Hence, there is exactly enough sodium carbonate.

Answer:

That should be Hydrogen.

So The second option Is legit!

Answer:

NCl₃

Explanation:

From the question given above, the following data were obtained:

Mass of nitrogen (N) = 0.77 mg

Mass of chlorine (Cl) = 6.61 mg

Empirical formula =?

The empirical formula of the compound can be obtained as follow:

N = 0.77 mg

Cl = 6.61 mg

Divide by their molar mass

N = 0.77 / 14 = 0.055

Cl = 6.61 / 35.5 = 0.186

Divide by the smallest

N = 0.055 / 0.055 = 1

Cl = 0.186 /0.055 = 3

Therefore, the empirical formula of the compound is NCl₃

Answer:

1. Empirical formula => C₂H₃O

2. Molecular formula => C₆H₉O₃

Explanation:

From the question given above, the following data were obtained:

Mass of compound = 50 g

Mass of Carbon = 24.66 g

Mass of Hydrogen = 3.43 g

Molecular weight of compound = 146.0 amu

Empirical formula =?

Molecular formula =?

Next, we shall determine the mass of oxygen in the compound. This can be obtained as follow:

Mass of compound = 50 g

Mass of C = 24.66 g

Mass of H = 3.43 g

Mass of O =?

Mass of O = mass of compound – ( mass of C + mass of H)

= 50 – (24.66 + 3.43)

= 50 – 28.09

= 21.91 g

1. Determination of the empirical formula.

Mass of C = 24.66 g

Mass of H = 3.43 g

Mass of O = 21.91 g

Divide by their molar mass

C = 24.66 / 12 = 2.055

H = 3.43 / 1 = 3.43

O = 21.91 / 16 = 1.369

Divide by the smallest

C = 2.055 / 1.369 = 2

H = 3.43 / 1.369 = 3

O = 1.369 / 1.369 = 1

Therefore, the empirical formula of the compound is C₂H₃O

2. Determination of the molecular formula.

Molecular weight of compound = 146.0 amu

Empirical formula => C₂H₃O

Molecular formula =?

Molecular formula = [C₂H₃O]ₙ = molecular weight

Thus,

[C₂H₃O]ₙ = 146

[(12×2) + (3×1) + 16]n = 146

[24 + 3 + 16]n = 146

43n = 146

Divide both side by 43

n = 146 / 43

n = 3

Molecular formula = [C₂H₃O]ₙ

Molecular formula = [C₂H₃O]₃

Molecular formula = C₆H₉O₃

Answer:

[tex](NH_4)_3PO_4(aq)+3NaCl(aq)\rightarrow 3NH_4Cl(aq)+Na_3PO_4(aq)[/tex]

Explanation:

Hello there!

In this case, according to the given information, we can set up the appropriate chemical equation when ammonium phosphate reacts with sodium chloride in aqueous solution:

[tex](NH_4)_3PO_4(aq)+NaCl(aq)\rightarrow NH_4Cl(aq)+Na_3PO_4(aq)[/tex]

Which stands for a double replacement reaction, whereby ammonium changes phosphate to chloride and sodium changes chloride to phosphate on the products side. In addition, we can balance the aforementioned equation as shown below:

[tex](NH_4)_3PO_4(aq)+3NaCl(aq)\rightarrow 3NH_4Cl(aq)+Na_3PO_4(aq)[/tex]

Regards!

We are given:

Initial concentration of HA: 0.200 Molar

The acid is 9.4% ionized

Dissociation constant (α) = (Percent Ionized) / 100 = 0.094

Molar concentration of H+ = 0.0188

Let's Chill! (making the ICE box):

Reaction:       HA         ⇄       H⁺      +      A⁻

Initial:           0.200M               -                -

Equilibrium: 0.200(1-α)      0.200α       0.200α

while we're here, let's confirm the given equilibrium concentration of H⁺ ions

from the table here, we can see that the equilibrium concentration of H⁺ ions is 0.200α, we know that α = 0.094

[H⁺] = 0.200α = 0.200 * 0.094 = 0.0188 M

which means that we're on the right track

We're basically scientists at this point (finding the dissociation constant):

Acid dissociation is nothing but the equilibrium constant, but for the dissociation of Acids

From the reaction above, we can write the equation of the acid dissociation constant:

Ka = [H⁺][A⁻] / [HA]

now, let's take the values from the 'equilibrium' row of the ice box the plug those in this equation

Ka = (0.200α)(0.200α) / [0.200(1-α)]

Ka = (0.200α)²/[0.200(1-α)]

plugging the value of α

Ka = (0.200*0.094)² / [0.200(0.906)]

Ka = (0.0188)² / 0.1812

Ka = 1.95 * 10⁻³

The question is incomplete. The complete question is :

C. Balance these fossil-fuel combustion reactions. (1 point)

C8H18(g) + 12.5O2(g) →    ____CO2(g) + 9H2O(g) + heat

CH4(g) + ____O2(g) →     ____CO2(g) + ____H2O(g) + heat

C3H8(g) + ____O2(g) →    ____CO2(g) + ____H2O(g) + heat

C6H6(g) + ____O2(g)  →   ____CO2(g) + ____H2O(g) + heat

Solution :

C8H18(g) + 12.5O2(g) →    __8__CO2(g) + 9H2O(g) + heat

When 1 part of octane reacts with 12.5 parts of oxygen, it gives 8 parts of carbon dioxide and 9 parts of water along with liberation of energy.

CH4(g) + __2__O2(g) →     __1__CO2(g) + __2__H2O(g) + heat

When 1 part of methane reacts with 2 parts of oxygen, it gives 1 part of carbon dioxide and 2 parts of water along with liberation of energy.

C3H8(g) + __5__O2(g) →    __3__CO2(g) + __4__H2O(g) + heat

When 1 part of propane reacts with 5 parts of oxygen, it gives 3 part of carbon dioxide and 4 parts of water along with liberation of energy.

C6H6(g) + __1/2__O2(g)  →   __6__CO2(g) + __3__H2O(g) + heat

When 1 part of propane reacts with 1/2 parts of oxygen, it gives 6 part of carbon dioxide and 3 parts of water along with liberation of energy.

Answer:

0.144 M

Explanation:

First we convert 0.307 g of KHP (potassium hydrogen phthalate, KHC₈H₄O₄) into moles, using its molar mass:

1 mol of KHP reacts with 1 mol of NaOH, that means that in 10.40 mL of the NaOH solution there were 0.0015 moles of NaOH.

Now we calculate the molarity of the NaOH solution: