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matrenka [14]
3 years ago
8

Quartz,SiO2,contains 46.7% silicon. What mass of silicon is present in 381 g of quartz?

Chemistry
1 answer:
swat323 years ago
4 0

Answer:

119 g.

Explanation:

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Given the following, determine ΔG°f at 298 K for SnO. Sn(s) + SnO2(s) → 2SnO(s) ; ΔG° = 12.0 kJ at 298K
Virty [35]

Answer:

The value of change in Gibbs free energy for tin(II) oxide solid is -251.9 kJ/mol.

Explanation:

Sn(s) + SnO_2(s)\rightarrow 2SnO(s), \Delta G_{f}^{o} = 12.0 kJ

\Delta G_{f,SnO_2}^{o}= -515.8kJ/mol

\Delta G_{f,Sn}^{o}= 0 kJ/mol

\Delta G_{f,SnO}^{o}=?

\Delta G_{f}^{o}=\sum ((\Delta G_{f}^{o})_ {products})-\sum ((\Delta G_{f}^{o})_ {reactants})

12.0 kJ=(2 mol\times \Delta G_{f,SnO}^{o})-(1mol\times 0 kJ/mol+1 mol\times -515.8 kJ/mol)

\Delta G_{f,SnO}^{o}=-251.9 kJ/mol

The value of change in Gibbs free energy for tin(II) oxide solid is -251.9 kJ/mol.

3 0
3 years ago
Can somebody answer this please
Murrr4er [49]

The answer should be A.

7 0
3 years ago
2. Why should a magnesium ribbon be cleaned before burning in air ?​
Nesterboy [21]
To remove magnesium oxide layer from the ribbon which may prevent or slow down the burning of magnesium ribbon.
8 0
3 years ago
1. What are the differences between lonic and covalent bonds?
zaharov [31]

Answer: Ionic bonds result from transfer of electrons, whereas covalent bonds are formed by sharing. ... Ionic bonds are electrostatic in nature, resulting from that attraction of positive and negative ions that result from the electron transfer process; charge separation between covalently bonded atoms is less extreme.

Explanation:

3 0
3 years ago
How much heat energy is required to convert 48.3 g of solid ethanol at -114.5 degree C to gasesous ethanol at 135.3 degree C? Th
OLEGan [10]

Answer:

7.21 × 10⁴ J

Explanation:

Ethanol is solid below -114.5°c, liquid between -114.5°C and 78.4°C, and gaseous above 78.4°C.

<em>How much heat energy is required to convert 48.3 g of solid ethanol at -114.5°C to gaseous ethanol at 135.3 °C?</em>

<em />

We need to calculate the heat required in different stages and then add them.

The moles of ethanol are:

48.3g.\frac{1mol}{46.07g} =1.05mol

Solid-liquid transition

Q₁ = ΔHfus . n = (4.60 kJ/mol) . 1.05 mol = 4.83 kJ = 4.83 × 10³ J

where,

ΔHfus: molar heat of fusion

n: moles

Liquid: from -114.5°C to 78.4°C

Q₂ = c(l) . m . ΔT = (2.45 J/g.°C) . 48.3g . [78.4°C-(-114.5°C)] = 2.28 × 10⁴ J

where,

c(l): specific heat capacity of the liquid

ΔT: change in the temperature

Liquid-gas transition

Q₃ = ΔHvap . n = (38.56 kJ/mol) . 1.05 mol = 40.5 kJ = 40.5 × 10³ J

where,

ΔHvap: molar heat of vaporization

Gas: from 78.4°C to 135.3°C

Q₄ = c(g) . m . ΔT = (1.43 J/g.°C) . 48.3g . (135.3°C-78.4°C) = 3.93 × 10³ J

where

c(g): specific heat capacity of the gas

Total heat required

Q₁ + Q₂ + Q₃ + Q₄ = 4.83 × 10³ J + 2.28 × 10⁴ J + 40.5 × 10³ J + 3.93 × 10³ J = 7.21 × 10⁴ J

3 0
3 years ago
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