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3 years ago

If snails and crayfish die, what happens to the other species?

Chemistry

2 answers:

Pani-rosa [81]3 years ago

8 0

Answer:

Other species will slowly die, because the species that eat snails and crayfish will not have anything to eat, then the thing that eats them will not have anything. This process will go on and on. So long story short populations will decrease, then off.

elixir [45]3 years ago

4 0

Crayfish are very intolerant of pollution and other human-generated fouling of their environment. ... This abundance may be due more to the acid-generated absence of fish which prey on crayfish than to a direct, positive influence of the acid on the crayfish itself.

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40.0 ml of an acetic acid of unknown concentration is titrated with 0.100 M NaOH. After 20.0 mL of the base solution has been ad

kirill115 [55]

Answer:

0.5 M

Explanation:

We have to start with the reaction between NaOH and CH3COOH:

$CH_3COOH~+~NaOH->CH_3COONa~+~H_2O$

We will have a 1:1 ratio between the acid and the base. The next step then would be the calculation of the moles of NaOH and his convertion to moles of CH3COOH.

$20~mL~\frac{1~L}{1000~mL} ~=~0.02~L$

$mol~=~0.1~M*0.02~L=0.02~mol~NaOH$

$0.02~mol~NaOH~\frac{1~mol~CH_3COOH}{1~mol~NaOH}=~0.02~mol~CH_3COOH$

The final step is the calculation of the concentration of the acid.

$M=\frac{0.02~mol~CH_3COOH}{0.04~L}=~0.5~M$

Due to the Ka value we can use the acetic acid as a strong acid.

6 0

3 years ago

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

In science, we like to develop explanations that we can use to predict the outcome of events and phenomena. Try to develop an ex

Kay [80]

The question is incomplete. The complete question is :

In science, we like to develop explanations that we can use to predict the outcome of events and phenomena. Try to develop an explanation that tells how much NaOH needs to be added to a beaker of HCl to cause the color to change. Your explanation can be something like: The color change will occur when [some amount] of NaOH is added because the color change occurs when [some condition]. The goal for your explanation is that it describes the outcome of this example, but can also be used to predict the outcome of other examples of this phenomenon. Here's an example explanation: The color of the solution will change when 40 ml of NaOH is added to a beaker of HCl because the color always changes when 40ml of base is added. Although this explanation works for this example, it probably won't work in examples where the flask contains a different amount of HCl, such as 30ml. Try to make an explanation that accurately predicts the outcome of other versions of this phenomenon.

Solution :

Consider the equation of the reaction between NaOH and $HCl$

NaOH (aq) + HCl (aq) → NaCl(aq) + $H_2O (l)$

The above equation tells us that $1 \text{mole}$ of $NaOH$ reacts with $1 \text{mole}$ of $HCl$ .

So at the equivalence point, the moles of NaOH added = moles of $HCl$ present.

If the volume of the $HCl$ taken = $V_1$ mL and the conc. of $HCl$ = $M_1$ mole/L

The volume of NaOH added up to the color change = $V_2 \text{ and conc of NaOH = M}_2$ mole/L

Moles of $HCl$ taken = $V_1 \ mL \times M_1 \ mol/100 \ mL = V_2M_2 \times 10^{-3}$ moles.

The color change will occur when the moles of NaOH added is equal to the moles of $HCl$ taken.

Thus when $V_1 M_1 \times 10^{-3} = V_2M_2 \times 10^{-3}$

or when $V_1M_1 = V_2M_2$

or $V_2=\frac{V_1M_1}{M_2}$ mL of NaOH added, we observe the color change.

Where $V_1, M_1$ are the volume and molarity of the $HCl$ taken.

$M_2$ is the molarity of NaOH added.

When both the NaOH and $HCl$ are of the same concentrations, i.e. if $M_1=M_2$ , then $V_2=V_1$

Or the 40 mL of $HCl$ will need 40 mL of NaOH for a color change and

30 mL of $HCl$ would need 30 mL of NaOH for the color change (provided the concentration $M_1=M_2$ )

7 0

3 years ago

Calculate the mass in grams, in 2.28 mol of H2SO4. Please show your work to receive credit.

solmaris [256]

Answer:

98g

Explanation:

h=1*2=2

s=32

0=16*4=64

64+32+2=98

4 0

3 years ago

How is calculating a weighted average

kirza4 [7]

Answer:

The Key difference between average vs weighted average is that simple average is nothing but simply adding up all the observation values and dividing the same by the total number of observations to calculate the average whereas weighted average is an average where each observation value will have a frequency assigned.

Explanation:

8 0

3 years ago