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2 years ago

If a response is towards a stimulus it's described as ___; if a response is away from the stimulus it's described as _.

Chemistry

1 answer:

crimeas [40]2 years ago

8 0

Answer: Positive tropism, negative tropism

Explanation:

Stimulus can be define as external and internal agent which generate a response in an organism. If the growth and action is towards the stimulus it is called as positive tropism. If the growth and action is away from the stimulus it is called as negative tropism. Example, the growth of the stem towards the sunlight is called positive tropism whereas the growth of the root away from the sunlight is called negative tropism. Here, sunlight is the stimulus.

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A precipitate forms when mixing solutions of sodium fluoride (NaF) and lead II nitrate (Pb(NO3)2). Complete and balance the net

Leya [2.2K]

Answer:

See explanation

Explanation:

The molecular equation shows all the compounds involved in the reaction.

The molecular equation is as follows;

2NaF(aq) + Pb(NO3)2(aq) -------> PbF2(s) + 2NaNO3(aq)

The complete ionic equation shows all the ions involved in the reaction

The complete ionic equation;

2Na^+(aq) + 2F^-(aq) + Pb^2+(aq) + 2NO3^-(aq) -------->PbF(s) + 2Na^+(aq) +2NO3^-(aq)

The net Ionic equation shows the ions that actually participated in the reaction

The net ionic equation is;

2F^-(aq) + Pb^2+(aq)--------> PbF(s)

3 0

2 years ago

The chemical reaction in which solid calcium oxide is treated liquid water is an example of what: A) decomposition B)combustion

laiz [17]

Answer:

The chemical reaction in which solid calcium oxide is treated liquid water is an example of Synthesis reaction. Hence, the answer is (D) Synthesis.

Explanation:

The formula of Calcium Oxide is CaO.

The formula of liquid water is H₂O.

Calcium Oxide reacts with water and forms Calcium Hydroxide. The Chemical equation is shown below.

CaO + H₂O --> Ca(OH)₂.

This is a Synthesis reaction because Ca(OH)₂ is synthesized by using Calcium Oxide and water.

The product of this reaction is calcium hydroxide, also known as slaked lime.

Thus, when calcium oxide reacts with water, slaked lime is produced.

Calcium oxide is also known as lime and is most commonly used for many purposes. It can be used for pH correction of water or for its disinfection (with excess lime).

8 0

3 years ago

2) A common "rule of thumb" -- for many reactions around room temperature is that the

babunello [35]

The question is incomplete. The complete question is :

A common "rule of thumb" for many reactions around room temperature is that the rate will double for each ten degree increase in temperature. Does the reaction you have studied seem to obey this rule? (Hint: Use your activation energy to calculate the ratio of rate constants at 300 and 310 Kelvin.)

Solutions :

If we consider the activation energy to be constant for the increase in 10 K temperature. (i.e. 300 K → 310 K), then the rate of the reaction will increase. This happens because of the change in the rate constant that leads to the change in overall rate of reaction.

Let's take :

$T_1=300 \ K$

$T_2=310 \ K$

The rate constant = $K_1 \text{ and } K_2$ respectively.

The activation energy and the Arhenius factor is same.

So by the arhenius equation,

$K_1 = Ae^{-\frac{E_a}{RT_1}}$ and $K_2 = Ae^{-\frac{E_a}{RT_2}}$

$\Rightarrow \frac{K_1}{K_2}= \frac{e^{-\frac{E_a}{RT_1}}}{e^{-\frac{E_a}{RT_2}}}$

$\Rightarrow \frac{K_1}{K_2}= e^{-\frac{E_a}{R}\left(\frac{1}{T_1}-\frac{1}{T_2}\right)}$

$\Rightarrow \ln \frac{K_1}{K_2}= - \frac{E_a}{R} \left(\frac{1}{T_1} -\frac{1}{T_2} \right)$

$\Rightarrow \ln \frac{K_2}{K_1}= \frac{E_a}{R} \left(\frac{1}{T_1} -\frac{1}{T_2} \right)$

Given, $E_a = 0.269$ J/mol

R = 8.314 J/mol/K

$\Rightarrow \ln \frac{K_2}{K_1}= \frac{0.269}{8.314} \left(\frac{1}{300} -\frac{1}{310} \right)$

$\Rightarrow \ln \frac{K_2}{K_1}= \frac{0.269}{8.314} \times \frac{10}{300 \times 310}$

$\Rightarrow \ln \frac{K_2}{K_1}= 3.479 \times 10^{-6}$

$\Rightarrow \frac{K_2}{K_1}= e^{3.479 \times 10^{-6}}$

$\Rightarrow \frac{K_2}{K_1}= 1$

∴ $K_2=K_1$

So, no this reaction does not seem to follow the thumb rule as its activation energy is very low.

8 0

2 years ago

Matter can be described by its

Anna11 [10]

Answer:

Physical properties can be observed, described, and measured without changing the material. ... To find the volume of a solid, pour liquid in a graduated cylinder and let a solid object sink in the liquid and measure how much volume is in the solid

3 0

2 years ago

Read 2 more answers

Mercury has an atomic number of 80 and a mass number of 200.

denis23 [38]

C. The mass number is the amount of Protons and electrons there are combined, so 200 - 80 is 120.

8 0

3 years ago

Read 2 more answers

If a response is towards a stimulus it's described as _______; if a response is away from the stimulus it's described as _____.

If a response is towards a stimulus it's described as ___; if a response is away from the stimulus it's described as _.