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choli [55]
3 years ago
12

What is a Pure element ?

Chemistry
1 answer:
inn [45]3 years ago
4 0
A substance where almost all have the same atomic number of protons
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Ancient Romans built often out of bricks and mortar. A key ingredient in their mortar was quicklime (calcium oxide), which they
velikii [3]

The question has missing information. At part 1 it is "Write a balanced chemical equation, including physical state symbols, for the decomposition of solid calcium carbonate (CaCO3) into solid calcium oxide and gaseous carbon dioxide."

Part 2. "Suppose 19.0 L of carbon dioxide gas are produced by this reaction, at a temperature of 290.0°C and pressure of exactly 1 atm. Calculate the mass of calcium carbonate that must have reacted (...)"

Answer:

41.0 g

Explanation:

1. Calcium oxide has molecular formula CaO and carbon dioxide CO₂, thus, the reaction will be:

CaCO₃(s) → CaO(s) + CO₂(g)

The equation is already balanced because there's the same number of each element on both sides.

2. First, let's calculate the number of moles of CO₂ produced by the ideal gas law:

PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant (0.082 atm.L/mol.K), and T is the temperature (290°C = 273 = 563 K).

1*19 = n*0.082*563

46.166n = 19

n = 0.4116 mol

By the stoichiometry of the reaction:

1 mol of CaCO₃ ------ 1 mol of CO₂

x ----- 0.4116 mol

By a simple direct three rule:

x = 0.4116 mol of CaCO₃.

The molar mass of the calcium carbonate is 100 g/mol, thus the mass (m) is the number of moles multiplied by it:

m = 0.4116*100

m = 41.16 g = 41.0 g

4 0
3 years ago
Which of these reactions involves an acid and a covalent base?
Juli2301 [7.4K]
I think the correct answer would be D. The reaction that involves an acid and a covalent base would be the reaction of sulfuric acid and water or H2SO4 + 2H2O → 2H3O+ + SO42– . The acid would be H2SO4 and the covalent base would be H2O since it is being held by covalent bonds and when in solution it will have equal amounts of OH- and H+ ions.
5 0
3 years ago
How many pounds of coal would you have to burn to generate enough heat to boil a 15 l kettle?
rjkz [21]
Note that
The heating value of standard coal is about 30,080 kJ/kg
1 L of water has a mass of 1.0 kg

The mass of 15 L of water = 15 kg.
The latent heat of vaporization of water is about 2260 kJ/kg,
 The energy required to boil 15 L of water is
(2260 kJ/kg)*(15 kg) = 33900 kJ

The mass of coal required to provide this energy is
(33900 kJ)/(30080 kJ/kg) = 1.127 kg

Because 1 kg = 2.205 lb, the mass of coal required is
(1.127 kg)*(2.205 lb/kg) = 2.485 lb

Answer: 2.49 lb (nearest hundredth)

7 0
3 years ago
Which Of The Following Is A Substance, Table Salt, Seawater, Or Sand?
klasskru [66]
Sand is because the other ones are liquid
6 0
2 years ago
Read 2 more answers
8. When rubidium and fluorine combine to produce the compound RbF, che ions
skelet666 [1.2K]

Answer:

The answer is C, both krypton and neon.

Explanation:

I got the answer wrong and my teacher told me that c is the right answer choice

8 0
3 years ago
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