(1.7 x 10-5 m) x (3.72 x 10-4 m) *

Which metal is more active than NI and less active than Zn?

Mademuasel [1]

Answer : The correct option is, (2) Cr (Chromium)

Explanation :

The reactivity series of metal are arranged of the reactivity from the highest to the lowest. Reactivity series is used to determine the products of the single displacement reactions. In the single displacement reaction, the most reactive metal displaces the least reactive metal.

From the given reactivity series we conclude that there are two metal (Mg and Cr) are more reactive metal than the Ni and there are two metal (Pb and Cr) are less reactive metal than the Zn. So, the Cr (Chromium) is the metal which is more active than Ni and less active than Zn.

Hence, the correct option is, (2) Cr

7 0

3 years ago

Read 2 more answers

he heat of fusion of tetrahydrofuran is . Calculate the change in entropy when of tetrahydrofuran melts at . Be sure your answer

lana [24]

Answer:

$\Delta S=1.8x10^{-3}\frac{kJ}{K}=1.8\frac{J}{K}$

Explanation:

Hello.

In this case, given the heat of fusion of THF to be 8.5 kJ/mol and freezing at -108.5 °C, for the required mass of 5.9 g, we can compute the entropy as:

$\Delta S=\frac{n*\Delta H}{T}$

Whereas n accounts for the moles which are computed below:

$n=5.9g*\frac{1mol}{72g} =0.082mol$

Thus, the entropy turns out:

$\Delta S=\frac{0.0819mol*8.5 kJ/mol}{(-108.5+273.15)K}\\\\\Delta S=1.8x10^{-3}\frac{kJ}{K}=1.8\frac{J}{K}$

Best regards.

3 0

3 years ago

Study the figures below which illustrate the steps in the following chemical reaction:

Tanya [424]

Answer:

Hello - this is Mrs. Gussman, your chemistry teacher. I wrote this exam question and posting it online is a violation of the academic integrity policy. Remove this post immediately.

Explanation:

7 0

2 years ago

Plz help its science

Naya [18.7K]

The answers are in the attached file

8 0

3 years ago

Calculate the theoretical carbonaceous and nitrogenous oxygen demand for:

serg [7]

Answer:

The correct answer is 129 mg and 232 mg.

Explanation:

Theoretical carbonaceous oxygen demand:

The reaction will be,

C₂H₆O₂ + 5/2 O₂ ⇒ 2CO₂ + 3H₂O

Thus, for one mole of C₂H₆O₂ (ethylene glycol), 2.5 moles of O₂ is needed.

The molecular mass of ethylene glycol is 62 grams per mole.

The given mass of ethylene glycol is 100 mg or 0.1 grams

The moles of ethylene glycol will be,

Moles = Weight/Molecular mass

= 0.1/62 = 1.613 × 10⁻³ mol

For 1.613 × 10⁻³ mol, the moles of O₂ will be,

= 2.5×1.613×10⁻³

= 4.0.×10⁻³ × 32mol

= 0.129 grams or 129 mg.

The theoretical nitrogenous oxygen demand is:

The reaction will be,

2NH₃-N + 9/2O₂ ⇒ 4HNO2 + H₂O

Thus, for 2 moles of NH₃-N, 4.5 moles of O₂ is needed,

Therefore, for 1 mol of NH₃-N, the oxygen required will be,

= 4.5/2 = 2.25 mol

The given mass of NH₃-N is 100 mg, the moles of NH₃-N will be,

Moles = 100×10⁻³/31 = 3.225 × 10⁻³ mol (The molecular mass of NH₃-N is 31 gram per mole)

The moles of O₂ is 2.25 × 3.225 × 10⁻³ = 7.258 × 10⁻³ mol.

Now the mass of O2 will be,

= 7.258 × 10⁻³ × 32

= 0.232 grams

= 232 mg

5 0

3 years ago