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3 years ago

B) A 120.0 g sample of ice at -10.0°C has placed on a heat source. How much energy must be

Chemistry

1 answer:

nikklg [1K]3 years ago

8 0

Answer:

Q = 27060 j

Explanation:

Given data:

Mass of sample = 120 g

Initial temperature = -10.0 °C

Final temperature = 100 °C

Heat added = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = T₂ - T₁

ΔT = 100- (-10)

ΔT = 110°C

Q = m.c. ΔT

Q = 120 g × 2.05 g/J.°C × 110°C

Q = 27060 j

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For the following reaction, 89.5 grams of iron are allowed to react with 36.9 grams of oxygen gas. iron (s) oxygen (g) iron(III)

hodyreva [135]

Answer:

122.3 g of Fe₂O₃ is the maximum amount formed

Explanation:

Our reactants for the reaction:

89.5 g of Fe

36.9 g of O₂

We convert the mass of each to moles:

89.5 g of Fe . 1 mol / 55.85 g = 1.60 moles

36.9 g of O₂ . 1mol / 32g = 1.15 moles

The reaction is 4Fe(s) + 3O₂(g) → 2Fe₂O₃ (s)

We determine the limiting reactant:

4 moles of Iron can react with 3 moles of O₂

Therefore 1.60 moles of Iron will react with (1.60 .3) / 4 = 1.2 moles

Oxygen is the limiting reactant; we need 1.2 moles, and we only have 1.15.

Then we work with the stoichiometry again.

3 moles of oxygen can produce 2 moles of Fe₂O₃

1.15 moles of oxygen may produce (1.15 . 2) / 3 = 0.766 moles of Fe₂O₃

We convert the moles to mass: 0.766 mol . 159.7 g /1mol = 122.3 g of Fe₂O₃

4 0

3 years ago

Which statement is most true about a hypothesis?

Alex73 [517]

This is from dictionary: <span>a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.
I would say it is 2</span>

3 0

4 years ago

How many acidic H+ ion is given by H3BO3 in aqueous solution?? ...?

notka56 [123]

Boric acid, H3BO3, in aqueous solution would only give out one H+ ion. As it is also produce OH ion and by hydrolysis it produces one proton. <span>All the boron compounds (BX3) are having only 6 valence electrons in it and should follow the octet rule by taking another electron.</span>

B(OH)3 + 2 H2O → B(OH)4− + H3O

7 0

3 years ago

When water is electrolyzed, it splits into hydrogen and oxygen.

Westkost [7]

The mass of water is equal to the combined mass of hydrogen and oxygen.

This is defined as the quantity of matter in a physical body. The electrolysis reaction of water can be seen below:

2 H₂O ---> 2 H₂ + O₂

We can deduce that 36 grams of H₂O dissociated to give 4 grams of H₂ and 32 grams of O₂ which option D was chosen as the appropriate choice.

Read more about Mass here brainly.com/question/25121535

4 0

3 years ago

In an experiment, a 0.5297 g sample of diphenylacetylene (C14H10) is burned completely in a bomb calorimeter. The calorimeter is

V125BC [204]

Answer:

the Molar heat of Combustion of diphenylacetylene $(C_{14}H_{10})$ = $-6.931 *10^3 \ kJ/mol$

Explanation:

Given that:

mass of diphenylacetylene $(C_{14}H_{10})$ = 0.5297 g

Molar Mass of diphenylacetylene $(C_{14}H_{10})$ = 178.21 g/mol

Then number of moles of diphenylacetylene $(C_{14}H_{10})$ = $\frac{mass}{molar \ mass}$

= $\frac{0.5297 \ g }{178.24 \ g/mol}$

= 0.002972 mol

By applying the law of calorimeter;

Heat liberated by 0.002972 mole of diphenylacetylene $(C_{14}H_{10})$ = Heat absorbed by $H_2O$ + Heat absorbed by the calorimeter

Heat liberated by 0.002972 mole of diphenylacetylene $(C_{14}H_{10})$ = msΔT + cΔT

= 1369 g × 4.184 J g⁻¹°C⁻¹ × (26.05 - 22.95)°C + 916.9 J/°C (26.05 - 22.95)°C

= 17756.48 J + 2842.39 J

= 20598.87 J

Heat liberated by 0.002972 mole of diphenylacetylene $(C_{14}H_{10})$ = 20598.87 J

Heat liberated by 1 mole of diphenylacetylene $(C_{14}H_{10})$ will be = $\frac{20598.87 \ J}{0.002972 \ mol}$

= 6930979.139 J/mol

= 6930.98 kJ/mol

Since heat is liberated ; Then, the Molar heat of Combustion of diphenylacetylene $(C_{14}H_{10})$ = $-6.931 *10^3 \ kJ/mol$

3 0

3 years ago

Read 2 more answers