Sphalerite contains about 30% zinc. Calculate the maximum amount of zinc that could be obtained from 1000kg sphalerite.

A manganese electrode was oxidized electrically. If the mass of the electrode decreased by 225 mg during the passage of 1580 cou

qwelly [4]

Answer:

Oxidation state of Mn = +4

Explanation:

Atomic mass of Mn = 55g/mol

From Faraday's law of electrolysis,

Electrochemical equivalent = $\frac{mass}{charge}$

i.e Z = $\frac{m}{Q}$ = $\frac{0.225g}{1580C}$ = 0.0001424 g/C

But Equivalent weight, E = atomic mass ÷ valency = Z × 96,485

⇒ $\frac{55}{valency}$ = 0.0001424 × 96,485

∴ Valency of Mn = +4

8 0

3 years ago

HELP ASAP

In-s [12.5K]

Answer:

greenhouse effect is the same as global warming

Explanation:

they both mean warming of the earths surface

8 0

2 years ago

Choose a likely identity for X, Y, and Z in these structures. A central X atom is bonded to two chlorine atoms through single bo

natka813 [3]

Complete Question

The complete question is shown on the first uploaded image

Answer:

X is Be

Y is B

Z is O

Explanation:

In order to understand the solution, we need to that the an element form a bond based on

1 The number of valence electron available in its atom

2 The number of electron it require to attains its stable state i.e its Octet state

The number of valence electron for each of the option are

F = 7, N = 5 , O = 6 , C = 4 , B = 3 , Be = 2

Considering the first element

We see that X is donating two valence electron in its atom and it is donating it to 2 Cl as Cl only requires a single electron to achieve its stable state

Now looking option we can see that Be has two valence electron in it atom and in order for it to attain its stable state it needs to release the electron so the correct option for this question is Be

Considering the second element

We see that Y is donating three valence electron in its atom and it is donating it to 3 Cl as Cl only requires a single electron to achieve its stable state

Now looking option we can see that B has three valence electron in it atom and in order for it to attain its stable state it needs to release the valence electron so the correct option for this question is B

Considering the second element

We see that Z is donating two valence electron in its atom and it is donating it to 2 Cl as Cl only requires a single electron to achieve its stable state, also Z has 2 lone-pair valence electron

Now looking at the option we can see that O has 6 valence electron so if it donates 2 valence electron it will still be left with 4 - pair of electron

Therefore the correct option to this question is O

6 0

3 years ago

When a 0.245-g sample of benzoic acid is combusted in a bomb calorimeter, the temperature rises 1.643 ∘C . When a 0.260-g sample

sveticcg [70]

Answer:

The heat of combustion per moles of caffeine is 4220 kJ/mol

Explanation:

Step 1: Data given

⇒ When benzoic acid sample of 0.245 grams is burned the temperature rise is 1.643 °C

⇒ When 0.260 gram of caffeine is burned, the temperature rise is 1.436 °C

⇒ Heat of combustion of benzoic acid = 26.38 kJ/g

Step 2: Calculate the heat released: for combustion of benzoic acid

0.245 g benzoic acid * 26.38 kJ/g = 6.4631 kJ

Step 3: Calculate the heat capacity of the calorimeter:

c = Q/ΔT

Q = 6.4631 kJ / 1.643°C = 3.934 kJ/ °C

Step 4: Calculate moles of a 0.260 g sample of caffeine:

Moles caffeine = Mass caffeine / Molar mass caffeine

0.260 grams/ 194.19 g/mol = 0.0013389 moles

Step 5: Calculate heat released: for combustion of caffeine

Q = c * ΔT

Q = 3.934 kJ/°C * 1.436 °C = 5.65 kJ

Step 6: Calculate the heat of combustion per mole of caffeine

5.65 kJ / 0.0013389 moles = 4219.9 kJ/mol ≈ 4220 kJ/mol

The heat of combustion per moles of caffeine is 4220 kJ/mol

4 0

4 years ago

Can anyone please help me

mixas84 [53]

Q1. Chemical, Physical, Physical, Physical
(l am not 100% sure about the 4th answer)

Q2. All of the above

4 0

3 years ago