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3 years ago

Which of these is not an ecosystem service that benefits people?

Chemistry

1 answer:

slavikrds [6]3 years ago

6 0

Answer:

D. greenhouse gases

Explanation:

A great part of greenhouse gases has an antropogenic origin, that is, that such gases are consequence of human activity and interfere with heating and cooling processes due to sun radiation on earth. The increase on greenhouse gases is followed by an increase on mean temperatures, affecting ecosystem negativelly.

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A solution containing a mixture of metal cations was treated with dilute hcl and a precipitate formed. the solution was filtered

likoan [24]

If you really keep an eye on the flow chart, the only ions you can consider as being "Definitely not present" are: Cr3+, Fe3+, and Zn2+. The rest of the ions should be considered under "Possibly present", as we cannot conclude if any of the ions are "Definitely present".

6 0

3 years ago

Which statement accurately describes dark matter?

Mandarinka [93]

Answer:

C. It does not emit electromagnetic radiation.

Explanation:

Right now, Dark Matter is only a theory. Scientist proposed this to counter some of the strange phenomenon with matter in space.

Scientists know little about dark matter. Some say it's one of the driving forces of the universe. Currently, scientists have no way of measuring or identifying dark matter.

5 0

2 years ago

Read 2 more answers

In IR spectroscopy, we normally talk about "frequencies" when in reality we are referring to wavenumbers. What is the mathematic

Svetach [21]

Answer:

Here's what I get.

Explanation:

(b) Wavenumber and wavelength

The wavenumber is the distance over which a cycle repeats, that is, it is the number of waves in a unit distance.

$\bar \nu = \dfrac{1}{\lambda}$

Thus, if λ = 3 µm,

$\bar \nu = \dfrac{1}{3 \times 10^{-6} \text{ m}}= 3.3 \times 10^{5}\text{ m}^{-1} = \textbf{3300 cm}^{-1}$

(a) Wavenumber and frequency

Since

λ = c/f and 1/λ = f/c

the relation between wavenumber and frequency is

$\bar \nu = \mathbf{\dfrac{f}{c}}$

Thus, if f = 90 THz

$\bar \nu = \dfrac{90 \times 10^{12} \text{ s}^{-1}}{3 \times 10^{8} \text{ m$\cdot$ s}^{-1}}= 3 \times 10^{5} \text{ m}^{-1} = \textbf{3000 cm}^{-1}$

(c) Units

(i) Frequency

The units are s⁻¹ or Hz.

(ii) Wavelength

The SI base unit is metres, but infrared wavelengths are usually measured in micrometres (roughly 2.5 µm to 20 µm).

(iii) Wavenumber

The SI base unit is m⁻¹, but infrared wavenumbers are usually measured in cm⁻¹ (roughly 4000 cm⁻¹ to 500 cm⁻¹).

8 0

3 years ago

How many moles of oxygen gas are needed to produce 4 moles of carbon dioxide gas?

11111nata11111 [884]

Answer: 8 moles
Explanation:
Nc2H6= 4 mol
2C2H6 + 7O2 → 4CO2+6H2O
CO2=4/2⋅4
NCO2= 8 moles
( I write this on paper so the letters and format might be confusing) sorry!!

3 0

2 years ago

A student has four resistors. Each resistor has a resistance of 100 ohms.

ValentinkaMS [17]

Answer:

The minimum resistance is 25 ohms.

Explanation:

Resistance of each resistor is 100 ohms. When resistors are connected in parallel, the equivalent resistance is lowest. For parallel combination, the equivalent resistance is given by :

$\dfrac{1}{R}=\dfrac{1}{R_1}+\dfrac{1}{R_2}+....$

Here, all resistors are 100 ohms. So,

$\dfrac{1}{R}=\dfrac{1}{100}+\dfrac{1}{100}+\dfrac{1}{100}+\dfrac{1}{100}\\\\R=25\ \Omega$

So, the minimum resistance is 25 ohms.

7 0

3 years ago