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3 years ago

For which compound does 0.256 mole weigh 12.8 g?

1 answer:

6 0

Number of moles = $\frac{mass (g)}{Molar mass}$
so to calculate molar mass (Molecular weight of compound):
Molecular weight = $\frac{mass (g)}{number of moles}$
= $\frac{12.8 g}{0.256 mole}$ = 50 g / mole
Now we calculate molecular weight of each compound in choices:
a) C₂H₄O = 44
b) CO₂ = 44
c) CH₃Cl = 50.4 ALMOST 50 so this is the correct answer
d) C₂H₆ = 30

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Help me!!!<br> Pleaseeee!!!!

Sidana [21]

Answer:

0.862 J/gºC

Explanation:

The following data were obtained from the question:

Mass of metal (Mₘ) = 50 g

Initial temperature of metal (Tₘ) = 100 °C

Mass of water (Mᵥᵥ) = 400 g

Initial temperature of water (Tᵥᵥ) = 20 °C

Equilibrium temperature (Tₑ) = 22 °C

Specific heat capacity of water (Cᵥᵥ) = 4.2 J/gºC

Specific heat capacity of metal (Cₘ) =?

The specific heat capacity of the metal can be obtained as follow:

Heat lost by metal = MₘCₘ(Tₘ – Tₑ)

= 50 × Cₘ × (100 – 22)

= 50 × Cₘ × 78

= 3900 × Cₘ

Heat gained by water = MᵥᵥCᵥᵥ(Tₑ – Tᵥᵥ)

= 400 × 4.2 × (22 – 20)

= 400 × 4.2 × 2

= 3360 J

Heat lost by metal = Heat gained by water

3900 × Cₘ = 3360

Divide both side by 3900

Cₘ = 3360 / 3900

Cₘ = 0.862 J/gºC

Therefore, the specific heat capacity of the metal is 0.862 J/gºC

5 0

2 years ago

. The net ionic equation for the reaction that occurs during the titration of nitrous acid with sodium hydroxide is (a) HNO2 Na

hjlf

Answer:

$H^+_{(aq)}+OH^{-}_{(aq)}\rightarrow H_2O_{(l)}$

Explanation:

Complete ionic equation : In complete ionic equation, all the substance that are strong electrolyte and present in an aqueous are represented in the form of ions.

Net ionic equation : In the net ionic equations, we are not include the spectator ions in the equations.

Only the species which are present in aqueous state dissociate.

Spectator ions : The ions present on reactant and product side which do not participate in a reactions. The same ions present on both the sides.

(a)

The balanced molecular equation will be,

$HNO_2_{(aq)}+NaOH_{(aq)}\rightarrow H_2O_{(l)}+NaNO_2_{(aq)}$

The complete ionic equation in separated aqueous solution will be,

$H^+_{(aq)}+NO_2^-_{(aq)}+Na^+_{(aq)}+OH^{-}_{(aq)}\rightarrow H_2O_{(l)}+Na^+_{(aq)}+NO_2^-_{(aq)}$

In this equation the species present are, $Na^+\text{ and }NO_2^-$ are the spectator ions.

Hence, the net ionic equation contains specie is

$H^+_{(aq)}+OH^{-}_{(aq)}\rightarrow H_2O_{(l)}$

6 0

3 years ago

In what element will metallic bonding occur?

Hatshy [7]

D

A- Harvard university professor

6 0

3 years ago

An ostrich runs north in a straight line for 21 meters. She then turns around and runs 25 meters back toward her nest (south) on

drek231 [11]

The ostrich runs 21 N then goes back by 25 S

The displacement is -4 S

21 - 25 = -4

6 0

3 years ago

Estimate the ph of the resulting solution prepared by mixing 1.0 mole of solid disodium phosphate (na2hpo4) and 1.25 mole of hyd

GenaCL600 [577]

The HCl added = 1.25 moles

and the moles of Na2HPO4 = 1 mole

Now when acid is added in the given solution of Na2HPO4

One mole of H+ will react with one mole of Na2HPO4 to given one mole of NaH2PO4

Na2HPO4 + H+ ---> NaH2PO4

Now this one mole formed NaH2PO4 will further react with 0.25 moles of H+ left to form 0.25 moles of H3PO4 and 0.75 moles of NaH2PO4 will remain in the solution

So this will result into formation of a buffer of phosphoric acid and NaH2PO4

NaH2PO4 + H+ ---> H3PO4

pKa of H3PO4 = 2.1

so pH = pKa + log [salt] / [acid] = 2.1 + log [0.75 / 0.25] = 2.58

so the pH will be in between 2.1 to 7.2

7 0

3 years ago