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3 years ago

What are pesticides best described as

Chemistry

2 answers:

Ierofanga [76]3 years ago

5 0

Answer:

Pesticides are best described as toxic chemicals used to control pest populations.

Explanation:

Pest is a destructive insect or other animal that attacks crops. Pesticides are used by humans to allow crops to develop and be available to harvest, otherwise, a lot of plants would be destroyed and agriculture would be less efficient.

densk [106]3 years ago

4 0

Pesticides are best described as a substance used for destroying or killing insects and pests harmful to plants and animals.

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Be sure to answer all parts. The percent by mass of bicarbonate (HCO3−) in a certain Alka-Seltzer product is 32.5 percent. Calcu

pochemuha

Answer : The volume of $CO_2$ will be, 514.11 ml

Explanation :

The balanced chemical reaction will be,

$HCO_3^-+HCl\rightarrow Cl^-+H_2O+CO_2$

First we have to calculate the mass of $HCO_3^-$ in tablet.

$\text{Mass of }HCO_3^-\text{ in tablet}=32.5\% \times 3.79g=\frac{32.5}{100}\times 3.79g=1.23175g$

Now we have to calculate the moles of $HCO_3^-$ .

Molar mass of $HCO_3^-$ = 1 + 12 + 3(16) = 61 g/mole

$\text{Moles of }HCO_3^-=\frac{\text{Mass of }HCO_3^-}{\text{Molar mass of }HCO_3^-}=\frac{1.23175g}{61g/mole}=0.0202moles$

Now we have to calculate the moles of $CO_2$ .

From the balanced chemical reaction, we conclude that

As, 1 mole of $HCO_3^-$ react to give 1 mole of $CO_2$

So, 0.0202 mole of $HCO_3^-$ react to give 0.0202 mole of $CO_2$

The moles of $CO_2$ = 0.0202 mole

Now we have to calculate the volume of $CO_2$ by using ideal gas equation.

$PV=nRT$

where,

P = pressure of gas = 1.00 atm

V = volume of gas = ?

T = temperature of gas = $37^oC=273+37=310K$

n = number of moles of gas = 0.0202 mole

R = gas constant = 0.0821 L.atm/mole.K

Now put all the given values in the ideal gas equation, we get :

$(1.00atm)\times V=0.0202 mole\times (0.0821L.atm/mole.K)\times (310K)$

$V=0.51411L=514.11ml$

Therefore, the volume of $CO_2$ will be, 514.11 ml

6 0

2 years ago

Write a balanced equation for rusting. (Assume rust becomes Fe+2)

Stells [14]

Answer:

4Fe + 3O2 + 6H2O → 4Fe(OH)3

Explanation:

The chemical formula for rust is Fe2O3 and is commonly known as ferric oxide or iron oxide. The final product is a series of chemical reactions simplified below as- The rusting of the iron formula is simply 4Fe + 3O2 + 6H2O → 4Fe(OH)3. The rusting process requires both the elements of oxygen and water.

8 0

2 years ago

If 4520 kj of heat is needed to boil a sample of water, what is the mass of water

Cerrena [4.2K]

Answer:

1,085g of water

Explanation:

If we have the value 4520kj is because the question is related to Energy and heat capacity. In this case, the law and equation that we use is the following:

Q= m*C*Δt where;

Q in the heat, in this case: 4520kj

m is the mas

Δt= is the difference between final-initial temperature (change of temperature), in this exercise we don´t have temperatura change.

In order to determine the mass, I will have the same equation but finding m

m= Q/C*Δt without m=Q/C

So: m= 4,520J/4.18J/g°C

m= 1,0813 g

5 0

3 years ago

What is the molarity of a strong acid solution with a pH of 3?

Anna35 [415]

Answer:

Since HCl is a strong acid, it completely ionizes, and the pH of HCl in solution can be found from the concentration (molarity) of the H+ ions, by definition equal to 0.100 M. (The conjugate base of the acid, which is the chloride ion Cl–, would also have a concentration of 0.100 M.) The pH is thus –log(0.100) = 1.000.

Explanation:

6 0

2 years ago

2. HOW MUCH HEAT IS REQUIRED TO BE RELEASED WHEN

jarptica [38.1K]

Answer: -112200J

Explanation:

The amount of heat (Q) released from an heated substance depends on its Mass (M), specific heat capacity (C) and change in temperature (Φ)

Thus, Q = MCΦ

Since,

Q = ?

Mass of water vapour = 30.0g

C = 187 J/ G°C

Φ = (Final temperature - Initial temperature)

= 100°C - 120°C = -20°C

Then apply the formula, Q = MCΦ

Q = 30.0g x 187 J/ G°C x -20°C

Q = -112200J (The negative sign does indicates that heat was released to the surroundings)

Thus, -112200 joules of heat is released when cooling the superheated vapour.

5 0

3 years ago