This worm infects humans by getting into the blood stream. It gets a

Read the descriptions below of two substances and an experiment on each. Decide whether the result of the experiment tells you t

marissa [1.9K]

Answer:

Sample A is a mixture

Sample B is a mixture

Explanation:

For sample A, we are told that the originally yellow solid was dissolved and we obtained an orange powder at the bottom of the beaker. Subsequently, only about 30.0 g of solid was recovered out of the 50.0g of solid dissolved. This implies that the solid is not pure and must be a mixture. The other components of the mixture must have remained in solution accounting for the loss in mass of solid obtained.

For sample B, we are told that boiling started at 66.2°C and continued until 76.0°C. The implication of this is that B must be a mixture since it boils over a range of temperatures. Pure substances have a sharp boiling point.

7 0

2 years ago

Gaseous methane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water . Suppose 9.6 g of methane is

lianna [129]

Answer:

21.6 g

Explanation:

The reaction that takes place is:

CH₄ + 2O₂ → CO₂ + 2H₂O

First we convert the given masses of both reactants into moles, using their respective molar masses:

9.6 g CH₄ ÷ 16 g/mol = 0.6 mol CH₄

64.9 g O₂ ÷ 32 g/mol = 2.03 mol O₂

0.6 moles of CH₄ would react completely with (2 * 0.6) 1.2 moles of O₂. As there are more O₂ moles than required, O₂ is the reactant in excess and CH₄ is the limiting reactant.

Now we calculate how many moles of water are produced, using the number of moles of the limiting reactant:

0.6 mol CH₄ * $\frac{2molH_2O}{1molCH_4}$ = 1.2 mol H₂O

Finally we convert 1.2 moles of water into grams, using its molar mass:

1.2 mol * 18 g/mol = 21.6 g

4 0

2 years ago

Which of the following sources of radiation produced from nuclear power plants poses the largest threat to humans?

oee [108]

The nuclear reactor inside the facility

8 0

3 years ago

Read 2 more answers

Using the Bohr model, determine the energy in joules of the photon produced when an electron in a Li2+ ion moves from the orbit

djverab [1.8K]

Answer:

1.64x10⁻¹⁸ J

Explanation:

By the Bohr model, the electrons surround the nucleus of the atom in shells or levels of energy. Each one has it's energy, and the electron doesn't fall to the nucleus because it can reach another level of energy, and then return to its level.

When the electrons go to another level, it absorbs energy, and then, when return, this energy is released, as a photon (generally as luminous energy). The value of the energy can be calculated by:

E = hc/λ

Where h is the Planck constant (6.626x10⁻³⁴ J.s), c is the light speed (3.00x10⁸ m/s), and λ is the wavelength of the photon.

The wavelength can be calculated by:

1/λ = R*(1/nf² - 1/ni²)

Where R is the Rydberg constant (1.097x10⁷ m⁻¹), nf is the final orbit, and ni the initial orbit. So:

1/λ = 1.097x10⁷ *(1/1² - 1/2²)

1/λ = 8.227x10⁶

λ = 1.215x10⁻⁷ m

So, the energy is:

E = (6.626x10⁻³⁴ * 3.00x10⁸)/(1.215x10⁻⁷)

E = 1.64x10⁻¹⁸ J

3 0

3 years ago

Define natural gas, liquefied petroleum gas (LPG), and liquefied natural gas (LNG). What three countries have most of the world’

mrs_skeptik [129]

Answer:

The answer is treated below.

Explanation:

Natural gas: Natural gas is not used in its pure form; it is processed and converted into cleaner fuel for consumption. It is a fossil fuel composed almost entirely of methane, but contain small amounts of other gases, including ethane, propane, pentane and butane. It is a combustible, gaseous mixture of simple hydrocarbon compounds, usually found in deep underground reservoirs formed by porous rock. Natural gas is mainly used as fuel for generating heat and electricity.

Liquefied petroleum gas (LPG): Liquefied Petroleum Gas is a byproduct of natural gas and oil extraction and crude oil refining . At room temperature, liquefied petroleum gas is a colourless and odourless gas which consists generally of butane (C4H10) or propane (C3H8) or a mixture of both.

Liquefied natural gas (LNG): Is natural gas that has been liquefied for ease of transport or storage. It is refrigerated to a very low temperature (-162 Celsius). At this temperature it becomes an odourless, non-toxic liquid that can be safely transported over long distances.

Three countries that have most of the world’s natural gas reserves

Russia
Iran
Qatar

Major advantages of using conventional natural gas as an energy resource:

It is less expensive when compared to other fossil fuels.
It is safer and easier to store when compared to other fossil fuels

Major disadvantages of using conventional natural gas as an energy resource:

It costs more to recover the remaining natural gas because of flow, access, etc.
It is not a renewable source.
it is a combustible material, It must be handled with care.
It does not contribute to greenhouse gases.

Three sources of unconventional natural gas :

Tight Gas
Shale Gas
Coalbed Methane

Major problems related to the use of Tight Gas

When Hydrofluoric acid is used to release tight gas in reserves it potentially an issue simply because the substance is so dangerous. A spill or a leak could harm workers and pollute groundwater for uses.

Major problems related to the use of Shale Gas

Risk of ground and surface water contamination.
Have impacts on air quality.

Major problems related to the use of Coalbed Methane

The development of coalbed methane will result to soil disturbance from construction of wells, roads, and the associated pipeline and electric power rights-of-ways.
It has impact on wildlife.

8 0

3 years ago