Answer:
Explanation:
Cheese, Meat, dough, Sauce
The element with the nlx notation of 5d2 in the periodic table is hafnium with a symbol of hf. It is a chemical element and has an atomic number 72. H<span>afnium chemically resembles zirconium and is found in many zirconium minerals but it is a complete contrast of zirconium which is also chemically similar to hafnium.</span>
<span>Answer:
For this problem, you would need to know the specific heat of water, that is, the amount of energy required to raise the temperature of 1 g of water by 1 degree C. The formula is q = c X m X delta T, where q is the specific heat of water, m is the mass and delta T is the change in temperature. If we look up the specific heat of water, we find it is 4.184 J/(g X degree C). The temperature of the water went up 20 degrees.
4.184 x 713 x 20.0 = 59700 J to 3 significant digits, or 59.7 kJ.
Now, that is the energy to form B2O3 from 1 gram of boron. If we want kJ/mole, we need to do a little more work.
To find the number of moles of Boron contained in 1 gram, we need to know the gram atomic mass of Boron, which is 10.811. Dividing 1 gram of boron by 10.811 gives us .0925 moles of boron. Since it takes 2 moles of boron to make 1 mole B2O3, we would divide the number of moles of boron by two to get the number of moles of B2O3.
.0925/2 = .0462 moles...so you would divide the energy in KJ by the number of moles to get KJ/mole. 59.7/.0462 = 1290 KJ/mole.</span>
Answer:
Explanation:
The vapor pressure of diethyl ether (ether) is 463.57 mm Hg at 25 °C. A nonvolatile, nonelectrolyte that dissolves in diethyl ether is aspirin. Calculate the vapor pressure of the solution at 25 °C when 14.88 grams of aspirin, C9H8O4 (180.1 g/mol), are dissolved in 269.2 grams of diethyl ether. diethyl ether = CH3CH2OCH2CH3 = 74.12 g/mol.
mol of C4H10O = mass of C4H10O / molar mass of C4H10O
= 242.1 g / 74.12 g/mol
= 3.266 mol
mol of C9H8O4 = mass of C9H8O4 / molar mass of C9H8O4
= 10.33 g / 180.1 g/mol
= 0.05736 mol
mole fraction of C4H10O,
X = mole of CHH1O0 / total mol
= (3.266)/(3.266 + 0.05736)
= 0.9827
now use:
P = Po*X
P = 463.57 * 0.9827
= 455.6 mm Hg
Answer:
Net ionic equation for the reaction between MgCl₂ and NaOH in water:
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Net ionic equation for the reaction between MgSO₄ and BaCl₂ in water:
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Explanation:
Start by finding the chemical equations for each reaction:
MgCl₂ reacts with NaOH to form Mg(OH)₂ and NaCl. This reaction is a double decomposition reaction (a.k.a. double replacement reaction, salt metathesis reaction.) This reaction is feasible because one of the products, Mg(OH)₂, is weakly soluble in water and exists as a solid precipitate.
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MgSO₄ reacts with BaCl₂ in a double decomposition reaction to produce BaSO₄ and MgCl₂. Similarly, the solid product BaSO₄ makes this reaction is feasible.
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How to rewrite a chemical equation to produce a net ionic equation?
- Rewrite all reactants and products that ionizes completely in the solution as ions.
- Eliminate ions that exist on both sides of the equation to produce a net ionic equation.
Typical classes of chemicals that ionize completely in water:
- Soluble salts,
- Strong acids, and
- Strong bases.
Keep the formula of salts that are not soluble in water, weak acids, weak bases, and water unchanged.
Take the first reaction as an example, note the coefficients:
- MgCl₂ is a salt and is soluble in water. Each unit of MgCl₂ can be written as
and
. - NaOH is a strong base. Each unit of NaOH can be written as
and
. - Mg(OH)₂ is a weak base and should not be written.
- NaCl is a salt and is soluble in water. Each unit of NaCl can be written as
and
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Ions on both sides of the equation:
, and
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Add the state symbols:
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For the second reaction:
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