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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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Write a nuclear equation for the alpha decay of 23892U.23892U → 0−1e + 23893Np23892U → 10n + 23792U23892U → 42He + 23490Th23892U

romanna [79]

Answer:

23892U=23490Th +42He

Explanation:

In alpha decay, the daughter nucleus is two units less than the parent in atomic number. The mass number also decreases by 4 units. The daughter is thus found two places before the parent in the periodic table.

5 0

3 years ago

Does the mineral cobalt have cleavage or fracture?.

marishachu [46]

I'm pretty sure that it's fracture, Not sure though

4 0

3 years ago

Air containing 0.04% carbon dioxide is pumped into a room whose volume is 6000 ft3. The air is pumped in at a rate of 2000 ft3/m

koban [17]

Here is the full question:

Air containing 0.04% carbon dioxide is pumped into a room whose volume is 6000 ft3. The air is pumped in at a rate of 2000 ft3/min, and the circulated air is then pumped out at the same rate. If there is an initial concentration of 0.2% carbon dioxide, determine the subsequent amount in the room at any time.

What is the concentration at 10 minutes? (Round your answer to three decimal places.

Answer:

0.046 %

Explanation:

The rate-in;

$R_{in}$ $= \frac{0.04}{100}*2000$

$R_{in}$ = 0.8

The rate-out

$R_{out}$ = $\frac{A}{6000}*2000$

$R_{out}$ = $\frac{A}{3}$

We can say that:

$\frac{dA}{dt}=$ $0.8-\frac{A}{3}$

where;

A(0)= 0.2% × 6000

A(0)= 0.002 × 6000

A(0)= 12

$\frac{dA}{dt} +\frac{A}{3} =0.8$

Integration of the above linear equation =

$e^{\int\limits \frac {1}{3}dt } =$ $e^{\frac{1}{3}t$

so we have:

$e^{\frac{1}{3}t}\frac{dA}{dt}} +\frac{1}{3}e^{\frac{1}{3}t}A$ $= 0.8e^{\frac{1}{3}t$

$\frac{d}{dt}[e^{\frac{1}{3}t}A]$ $= 0.8e^{\frac{1}{3}t$

$Ae^{\frac{1}{3}t} =2.4e\frac{1}{3}t +C$

∴ $A(t) = 2.4 +Ce^{-\frac{1}{3}t$

Since A(0) = 12

Then;

$12 =2.4 + Ce^{-\frac{1}{3}}(0)$

$C= 12-2.4$

$C =9.6$

Hence;

$A(t) = 2.4 +9.6e^{-\frac{t}{3}}$

$A(0) = 2.4 +9.6e^{-\frac{10}{3}}$

$A(t) = 2.74$

∴ the concentration at 10 minutes is ;

= $\frac{2.74}{6000}*100$ %

= 0.0456667 %

= 0.046% to three decimal places

7 0

3 years ago

Hello! could anyone help me? i don't really understand. Thank you!!

liq [111]

I'm curious on what it is but I wish I could help

7 0

2 years ago

When wood burns, the mass of the ash is less than the mass of the original wood. Yet the law of conservation of matter says that

satela [25.4K]

Explanation:

According to the law of the conservation of mass, 'mass is conserved in a chemical reaction. The mass cannot be created nor be destroyed in a chemical process'.

This law holds true for the burning of wood also. Although the wood burns to produce ash which weighs less than wood but also, it produces some soot and other gases and the sum of the masses of all these is equal to the sum of the masses of wood and oxygen that reacted with it.

7 0

2 years ago