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goblinko [34]
3 years ago
15

A 3.540-g sample of an unknown metal M is burned in the presence of excess oxygen, producing the oxide M2O3(s) and liberating 18

.56 kJ of heat at constant pressure. What is the identity of the metal? 4M(s) + 3O2(g) → 2M2O3(s) SubstanceΔH°f (kJ/mol) Yb2O3(s)–1814.6 Tb2O3(s)–1865.2 Sm2O3(s)–1823.0 Sc2O3(s)–1908.8 Y2O3(s)–1905.3 a) Sm b) Tb c) Y d) Sc e) Yb
Chemistry
1 answer:
pshichka [43]3 years ago
3 0

Answer:

a) Sm

Explanation:

Hello,

This substantiation could be done by knowing how to compute the released energy for 1 mol the oxide. Thus, for Sm, the computation turns out into:

Q=-1823.0\frac{kJ}{mol}*\frac{1molSm_2O_3}{348.72gSm_2O_3} *3.540gSm_2O_3\\Q=-18.5kJ

The sign just indicates that the heat is released due to the chemical reaction and it matches with the indicated heat in the statement.

Best regards.

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Read 2 more answers
What volume of an hcl solution with a ph of 1.3 can be neutralized by one dose of milk of magnesia?
kvv77 [185]

274 mL H3 O+ and fully neutralized

It will take one teaspoon of Mg(OH)2 to completely neutralize 2.00×10^2mL  of H3O+.

<h3>What is the purpose of milk of magnesia?</h3>
  • For a brief period of time, this medicine is used to relieve sporadic constipation.
  • It is an osmotic laxative, which means that it works by drawing water into the intestines, which aids in causing bowel movement.
<h3>What dosage of milk of magnesia is recommended for constipation?</h3>
  • Take Milk of Magnesia once day, preferably before bed, in divided doses, or as prescribed by a physician.
  • suggested dosage: 30 mL to 60 mL for adults and kids 12 years of age and older. 15 mL to 30 mL for children aged 6 to 11 years.

learn more about milk of magnesia here

brainly.com/question/15178597

#SPJ4

the question you are looking for is

People often take milk of magnesia to reduce the discomfort associated with acid stomach or heartburn. The recommended dose is 1 teaspoon, which contains 4.00x 10^{2} mg of Mg(OH)_2. What volume of an HCl solution with a pH of 1.3 can be neutralized by one dose of milk of magnesia? If the stomach contains 2.00x10^{2}mL of pH 1.3 solution, is all the acid neutralized? If not, what fraction is neutralized?

7 0
1 year ago
PLEASE HELP ASAP!
choli [55]

Answer:

\large \boxed{\text{D. 710 g}}

Explanation:

1. Calculate the molar mass of Na₂SO₄

\begin{array}{ccc}\textbf{Atoms} &\textbf{M}_{\textbf{r}} & \textbf{Mass/u}\\\text{2Na} & 23 & 46\\\text{1S} & 32 & 32\\\text{4O}&16 & 64\\&\text{TOTAL =} & \mathbf{142}\\\end{array}

The molar mass of Na₂SO₄ is 142 g/mol.

2. Calculate the moles of Na₂SO₄

\text{Moles of Na$_{2}$SO}_{4} = \text{2.5 L solution} \times \dfrac{\text{2.0 mol Na$_{2}$SO}_{4}}{\text{1 L solution}} = \text{5.0 mol Na$_{2}$SO}_{4}

3. Calculate the mass of Na₂SO₄

\text{Mass of Na$_{2}$SO}_{4} = \text{5.0 mol Na$_{2}$SO}_{4} \times \dfrac{\text{142 g Na$_{2}$SO}_{4}}{\text{1 mol Na$_{2}$SO}_{4}} = \text{710 g Na$_{2}$SO}_{4}\\\\\text{You need } \large \boxed{\textbf{710 g}} \text{ of Na$_{2}$SO}_{4}

6 0
3 years ago
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