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3 years ago

Of the following, which is most likely to result after a farmer sprays his crops with pesticides?

Chemistry

2 answers:

Marysya12 [62]3 years ago

7 0

The correct options are as follows:

1. D.

Pesticides are chemicals that are used by farmers to eliminate pests that are destroying their crops. Pesticides comes in various form and the methods used to apply them vary. Some of the pesticides are apply directly to the soil, in this case, the pesticide can move into the water level of the area and contaminate the water source in that environment. If this happens, the water source in that area will test positive for pesticides.

2. A

Due to different human activities, the quantity of carbon dioxide that is available in the atmosphere these days has increase tremendously and this in turn has result in the amount of carbon dioxide that get dissolved in different water bodies, leading to the acidification of the water, which is unhealthy for the organisms living in the water. Also, carbon dioxide increase in the atmosphere leads to global warming, which leads to increase in the temperature of water bodies. The higher the temperature of the water bodies, the higher the quantity of carbon dioxide that get dissolved in the water. Dissolution of CO2 in water leads to water acidification, which can lead to fish kill.

Anastasy [175]3 years ago

6 0

Of the following, which is most likely to result after a farmer sprays his crops with pesticides?D. A neighbor’s well tests positive for pesticides.

Carbon dioxide is a colorless, odorless gas. Why is it considered a pollutant?
A. It gets into natural waters and kills fish.

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Suppose you have just added 100 ml of a solution containing 0.5 mol of acetic acid per liter to 400 ml of 0.5 m naoh. what is th

Tpy6a [65]

$pH = 13.5$

Explanation:

Sodium hydroxide completely ionizes in water to produce sodium ions and hydroxide ions. Hydroxide ions are in excess and neutralize all acetic acid added by the following ionic equation:

$\text{HAc} + \text{OH}^{-} \to \text{Ac}^{-} + \text{H}_2\text{O}$

The mixture would contain

$0.4 \times 0.5 - 0.1 \times 0.5 = 0.15 \; \text{mol}$ of $\text{OH}^{-}$ and
$0.1 \times 0.5 = 0.05 \; \text{mol}$ of $\text{Ac}^{-}$

if $\text{Ac}^{-}$ undergoes no hydrolysis; the solution is of volume $0.1 + 0.4 = 0.5 \; \text{L}$ after the mixing. The two species would thus be of concentration $0.30 \; \text{mol} \cdot \text{L}^{-1}$ and $0.10 \; \text{mol} \cdot \text{L}^{-1}$ , respectively.

Construct a RICE table for the hydrolysis of $\text{Ac}^{-}$ under a basic aqueous environment (with a negligible hydronium concentration.)

$\begin{array}{cccccccc} \text{R} & \text{Ac}^{-}(aq) &+ & \text{H}_2\text{O}(aq) & \leftrightharpoons & \text{HAc}(aq) & + & \text{OH}^{-} (aq)\\ \text{I} & 0.10 \; \text{M} & & & & & &0.30 \; \text{M}\\ \text{C} & -x \; \text{M}& & & & +x \; \text{M}& & +x \; \text{M} \\ \text{E} & (0.10 - x) \; \text{M} & & & & x \; \text{M} & & (0.30 +x) \; \text{M} \end{array}$

The question supplied the <em>acid</em> dissociation constant $pK_a$ for acetic acid $\text{HAc}$ ; however, calculating the hydrolysis equilibrium taking place in this basic mixture requires the <em>base</em> dissociation constant $pK_b$ for its conjugate base, $\text{Ac}^{-}$ . The following relationship relates the two quantities:

$pK_{b} (\text{Ac}^{-}) = pK_{w} - pK_{a}( \text{HAc})$

... where the water self-ionization constant $pK_w \approx 14$ under standard conditions. Thus $pK_{b} (\text{Ac}^{-}) = 14 - 4.7 = 9.3$ . By the definition of $pK_b$ :

$[\text{HAc} (aq)] \cdot [\text{OH}^{-} (aq)] / [\text{Ac}^{-} (aq) ] = K_b = 10^{-pK_{b}}$

$x \cdot (0.3 + x) / (0.1 - x) = 10^{-9.3}$

$x = 1.67 \times 10^{-10} \; \text{M} \approx 0 \; \text{M}$

$[\text{OH}^{-}] = 0.30 +x \approx 0.30 \; \text{M}$

$pH = pK_{w} - pOH = 14 + \text{log}_{10}[\text{OH}^{-}] = 14 + \text{log}_{10}{0.30} = 13.5$

6 0

3 years ago

A 0.300 m solution of hcl is prepared by adding some 1.50 m hcl to a 500 ml volumetric flask and diluting to the mark with deion

liberstina [14]

In dilution we add distilled water to decrease the concentration of required sample from high concentration to lower concentration
The law used for dilution:
M₁V₁]Before dilution = M₂V₂] After dilution
M₁ = 1.5 M
V₁ = ?
M₂ = 0.3 M
V₂ = 500 ml
1.5 * V₁ = 0.3 * 500 ml
so V₁ = 100 ml and it completed to 500 ml using 400 ml deionized water

8 0

3 years ago

The molar mass of a certain gas is 80.6 g. What is the density of the gas in g/L at STP?

vfiekz [6]

Using the ideal gas equation:
PV = nRT

Substituting n with mass / Mr
PV = mRT/Mr

Density = m/V
So rearranging:
Density = PMr/RT

P = 1 atm
R = 0.082 L atm / K mol
T = 273 K
Density = (1 x 80.6) / (0.082 x 273)
Density = 3.6 g / L

3 0

3 years ago

Find mass of 3 moles of water

EleoNora [17]

Answer:

54 g

Explanation:

1 mole of water = H2O

mass of 1 mole of H2O= mass of h2 + mass of o

= 2× mass of h +mass of o

= 2×1+16 =18 g

1 mole of water = 18g

3moles of water = 18×3g= 54g

6 0

3 years ago

Which statements about the structure of the periodic table are true?

Liono4ka [1.6K]

Answer:

Below are the statements which are true about the structure of the periodic table:

B: The inner transition elements are placed at the bottom of the periodic table for easy viewing.

D: The distribution of electrons in energy levels is responsible for the shape of the periodic table.

Explanation:

Point A:

As we know that in a periodic table there are 7 period s and 18 groups. So, the number of periods is evidently lesser than the number of groups. But the shape of periodic table is regular and rectangular so point A is false.

Point B:

The inner transition elements or -f block elements are put at the bottom for easy viewing. These are the elements that have the valence electrons only in the f-orbital's. Therefore, they are placed separately at the bottom side of the table so that they can be easily viewed or studied from there. So, point B is true.

Point C:

If we talk about option C, then it is very clear and true that considering a rectangular shape of the periodic table, the groups are vertically arranged and periods are horizontally arranged, therefore it is false.

Point D:

Atoms of all elements have definite electronic distribution in different energy levels like s, p d or f. This is a very prominent feature of periodic tale that elements are divided in specific blocks, s, p, d and f based on their electronic configurations. Therefore, it is true.

Point E:

We also know that no. of metals in a periodic table are more than the no. of non metals like almost 91 out of 118 elements are metals in periodic table. Therefore, the point E "Nonmetals take up more than half the area of the periodic table." is false.

Hope it helps!

5 0

2 years ago