Which of the following is equal to distance/time?

Calculate the atomic mass for copper using the weighted average mass method. Express your answer using two decimal places and in

tatuchka [14]

Answer:

63. 55 amu

Explanation:

Copper is known to exist in two different isotopes which are Cu-63 and Cu-65.

Cu-63 has an atomic mass of 62.93 amu and it has an abundance of 69.15%.

Similarly,

Cu-65 has an atomic mass of 64.93 amu and it has an abundance of 30.85%

Therefore, using the weighted average mass method, the atomic mass of copper is:

Atomic mass of copper = (0.6915*62.93) amu + (0.3085*64.93) amu = 43.52 amu + 20.03 amu = 63.55 amu

Thus, the atomic mass of copper (express in two decimal places) is 63.55 amu

8 0

3 years ago

If the edge length of the unit cell is 705.2 pm, what is the density of KI in g/cm3.

Kipish [7]

The density is 3.144 g / cm^3.

<u>Explanation</u>:

If effective number of atom in NaCl type structure, z = 4

a = 705.2 pm ⇒ In centimeter = 705.2 $\times$ 10^-10

Na = 6.023 $\times$ 10^23

density = (molecular weight) (z) / (Na) (a^3)

where molecular weight of KI is 166 g,

Z represents the atomic number

density = (molecular weight) (z) / (Na) (a^3)

= (166 $\times$ 4) / (6.023 $\times$ 10^23) $\times$ (705.2 $\times$ 10^-10)

density = 3.144 g / cm^3.

5 0

2 years ago

Name each of the following species for the following acid-base reactions. (The equilibrium lies to the right in each case, i.e.,

DaniilM [7]

Answer: a) $H_3O^++CH_3O^-\rightleftharpoons CH_3OH+H_2O$

acid : hydronium ion

base : methoxide ion

conjugate acid : methanol

conjugate base: water

b) $CH_3CH_2O^-+HCl\rightleftharpoons CH_3CH_2OH+Cl^-$

acid : hydrogen chloride

base : ethoxide ion

conjugate acid : ethanol

conjugate base: chloride ion

c) $NH_2^-+CH_3OH\rightleftharpoons NH_3+CH_3O^-$

acid : methanol

base : amide ion

conjugate acid : ammonia

conjugate base: methoxide ion

Explanation:

According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.

The species accepting a proton is considered as a base and after accepting a proton, it forms a conjugate acid.

The species losing a proton is considered as an acid and after loosing a proton, it forms a conjugate base

For the given chemical equation:

a) $H_3O^++CH_3O^-\rightleftharpoons CH_3OH+H_2O$

acid : hydronium ion

base : methoxide ion

conjugate acid : methanol

conjugate base: water

b) $CH_3CH_2O^-+HCl\rightleftharpoons CH_3CH_2OH+Cl^-$

acid : hydrogen chloride

base : ethoxide ion

conjugate acid : ethanol

conjugate base: chloride ion

c) $NH_2^-+CH_3OH\rightleftharpoons NH_3+CH_3O^-$

acid : methanol

base : amide ion

conjugate acid : ammonia

conjugate base: methoxide ion

.

3 0

2 years ago

Explain, in terms of electron configuration why atoms of the radioisotope produced by the sixth decay in the U-238 disintegratio

Troyanec [42]

Answer:

The reason they don't react is because Elements with full octets are stable, the Elements with no unpaired electrons do not react at all in the decay.

4 0

2 years ago

What mass of Hg will occupy a volume of 75.0 mL?

k0ka [10]

75.0 mL in liters:

75.0 / 1000 => 0.075 L

1 mole -------------------- 22.4 L ( at STP)
( moles Hg) ------------- 0.075 L

moles Hg = 0.075 x 1 / 22.4

moles = 0.075 / 22.4

= 0.00334 moles of Hg

Hg => 200.59 u

1 mole Hg ----------------- 200.59 g
<span>0.00334 moles Hg ----- ( mass Hg )
</span>
mass Hg = 200.59 x 0.00334 / 1

mass Hg = 0.6699 / 1

= 0.6699 g of Hg

7 0

3 years ago