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3 years ago

Which of the following is a pure substance?AirBloodCopperWood

Chemistry

2 answers:

krek1111 [17]3 years ago

4 0

Answer:

copper

Explanation:

its an element, its not mixed with anything else

Schach [20]3 years ago

4 0

The answer is "Copper" or option C. Air, and blood aren't pure substances but mixtures, wood is also a mixture which means the answer is copper. Pure Substances are is matter with composition and distinct chemical properties.

Hope this helps.

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If 25.16 g of chlorine react with 12.99 g of manganese metal, what is the empirical formula of the compound?

WARRIOR [948]

We use the given masses of the reactants to calculate the moles of Mn and Cl. Empirical formula represents the simplest mole ratio of atoms present in a compound.

Moles of Mn = $12.99 g Mn * \frac{1 mol Mn}{54.94 g Mn} = 0.236 mol Mn$

Moles of Cl = $25.16 g Cl_{2} *\frac{1 mol Cl_{2}}{70.91 g Cl_{2}} * \frac{2 mol Cl}{1 mol Cl_{2}}$ = 0.710 mol Cl

Simplest mole ratio: $Mn_{\frac{0.236}{0.236}}Cl_{\frac{0.710}{0.236}}$

So the empirical formula is $MnCl_{3}$

6 0

3 years ago

(a) Calculate the energy released by the alpha decay of 222 86Rn.

Alinara [238K]

Answer:

a). The energy released by the alpha decay of 222 Rn is to 218 Po :

= 5.596 MeV

b).The energy of the alpha particle is 5.5 MeV

c) The recoil energy of Po = 0.096 MeV

Explanation:

The equation for the alpha decay of Rn to Polonium is:

$_{86}^{222}\textrm{Rn}\rightarrow$ $_{2}^{4}\textrm{He}+_{84}^{218}\textrm{Po}$

The energy of the decay process can be calculated using:

$\Delta E=\Delta mc^{2}$

$\Delta m$ = Change in the mass

Mass of Po = 218.008965 u

Mass of He = 4.002603 u

Mass of Rn = 222.017576 u

$\Delta m$ = mass of Po + mass of He - mass of Rn

= 4.002603 + 218.008965-222.017576

= - 0.006008

$\Delta E=m(931.5MeV)$

$\Delta E=-0.006008\times 931.5MeV$

= -5.596 MeV

The negative sign means energy is released during the process.

b) The energy of the alpha particle is :

$\frac{Po\ mass }{Rn\ mass}\times E$

$\frac{218.0089}{222.0175}\times \Delta E$

$\frac{218.0089}{222.0175}\times 5.596$

= 5.494 MeV

= 5.5 MeV

c).

Recoil energy: When the parent nucleus is at rest before the decay then , there must be the some recoil of daughter nucleus to conserve the momentum.This is termed as recoil energy.

The energy of the recoil polonium atom :

The formula for recoil energy is :

The total energy - the kinetic energy

= 5.596 - 5.5

= 0.096 MeV

7 0

3 years ago

Describe the electron distribution in a polar-covalent bond and it's effect on the partial charges of the compound?

Artemon [7]

Answer:

In polar Covalent bonds, the electrons which are in bonded shifts towards an atom which has more valance electrons.

Explanation:

We know if an atom takes the electron it acquires a negative charge whereas if it gives an electron it acquires a positive charge in the ionic bond. But here we are talking about covalent bonds. Covalent bonds are those in which atoms share the electron instead of completely giving off the electron. If the atoms are identical in case of covalent bond that is 2 hydrogen atoms then this type of bonding is called pure covalent bonds but if the atoms linked in covalent bonds are different then it is called polar covalent bonds.

In this, the bonding electrons will shift towards an atom which has more valence electron thereby acquiring the partial negative charges and the other atom will acquire a partial positive charge. For example, HCl. In this the Chlorine atom is having more valence electron than hydrogen atom, and hence Chlorine atom has a partial negative charge and Hydrogen atom has a partial positive charge.

5 0

3 years ago

During a chemical change items are lost or gained to make new substance true or false

Otrada [13]

Answer:

If you meant Atoms then the answer is false

5 0

3 years ago

Which of the following apply to gases. Select all that apply.

alexira [117]

The answer is C , hope I helped

8 0

3 years ago

Which of the following is a pure substance?AirBloodCopperWood​

Which of the following is a pure substance?AirBloodCopperWood