Answer: 15.0
Explanation:
1) The chemical formula of silver nitrate is AgNO₃
2) The chemical formula of silver chloride is AgCl
3) Therefore, by mass balance you know that all the atoms of Ag in AgNO₃ will en up at the AgCl. This is a mole ratio 1:1.
4) Since, there are 15.0 moles of Ag atoms in 15.0 moles of AgNO₃, you conclude, using the 1: 1 ratio, that 15.0 moles of AgCl are produced.
B. farmer
C. painter
D. carpenter
b. polyatomic ion
c. multivalent ion
d. electron ion
Answer:
The correct answer is option b, that is, polyatomic ion.
Explanation:
A molecular ion also called polyatomic ion refers to a charged chemical species comprising two or more atoms bonded covalently with each other. The polyatomic ions comprise two or more non-metallic atoms. An example of a polyatomic ion is an ion of nitrate that comprises one atom of nitrogen and three atoms of oxygen. As the atoms in a polyatomic ion are bonded covalently, they are considered to possess a single charged unit.
Answer:
0.22 grams of magnesium
This seems too low, so check the calculations/
Explanation:
How is the heat delivered? Is the magnesium hot and added to the water? If so, at what temperature.
Is the heat generated from an exothermic chemical reaction?
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I'll assume here that the heat comes from the reaction of magnesium with water. The balanced equation is:
Mg + 2H2O = Mg(OH)2 + H2
It has a heat of reaction of −924.7 kJ/mol.
We need enough Mg to heat 30 ml of water from 22°C to 90°C. The specific heat of water is needed. It is 4.184 J/g-K. It tells us that 4.184 Joules are needed to raise the temperature of water by 1 degree K.
30 ml of water with density 1 gram/ml means we have 30 grams of water. (We'll ignore the water that is added from the chemical reaction.).
Lets calculate the Joules required to raise 30 grams of water from 22°C to 90°C. Note that the specific heat has units of g and Kelvin. Since we need a temperature change, the number value for ΔT is the same for both °C and °K. So the temperature change is +68°K.
We can now calculate the Joules required:
(30 grams H2O)*(4.184 J/g-K)*(+68°K) = 8535.4 Joules or 8.5 kJ to 2 sig figs.
The Mg/H2O heat of reaction of −924.7 kJ/mol. will allow us to calculate the amount of Mg needed to supply 8.5 kJ. The minus sign tells us that the reaction RELEASES energy (the energy leaves the "system" of Mg and H2O).
Calculate the moles of Mg needed to release 8.5 kJ:
(924.7 kJ/mole)*(x moles) = 8.5 kJ
x moles = 0.0092 moles
Whoa. That is only (0.0092 moles)*(24.03 g/mole) = 0.22 grams of magnesium
This seems low to me, so check on the heat of reaction figure I used. And don't let the hydrogen get away.
Answer:
pH=8.32
Explanation:
The relevant equilibrium for this problem is
F⁻ + H₂O ↔ HF + OH⁻
With a constant Kb of
Kb=
Kb=
To calculate the value of Kb we use the formula Kw=Ka*Kb, where Kw is the ionization constant of water, 1 * 10⁻¹⁴.
1 * 10⁻¹⁴ = 7.2*10⁻⁴ * Kb
Kb = 1.4 * 10⁻¹¹
So now we have
1.4 * 10⁻¹¹=
We make the assumption that x<<<0.30 M, so we can rewrite the equation of Kb as:
1.4 * 10⁻¹¹=
So [OH⁻]=2.05*10⁻⁶
Answer:
D- Radiation knocks electrons out of gas atoms, which allows the gas to conduct an electric current.
Explanation:
Edge 2021