How can an invasive species like weeds affect crops on a farm?

zvonat [6]

Answer:

7.941

Explanation:

You can look at a picture of the periodic table.To calculate the atomic mass of a single atom of an element, add up the mass of protons and neutrons. Example: Find the atomic mass of an isotope of carbon that has 7 neutrons. You can see from the periodic table that carbon has an atomic number of 6, which is its number of protons.

Hope I helped

3 0

3 years ago

A mixture of pepper and water is a suspension because ________ HELPPPP

malfutka [58]

It doesn't because pepper does not dissolve

7 0

3 years ago

What temperature will the water reach when 10.1 g CaO is dropped into a coffee cup containing 157 g H2O at 18.0°C if the followi

Zepler [3.9K]

Answer:

Final temperature attained by water = 34.6°C

Explanation:

The reaction of CaO and H₂O is an <em>exothermic reaction</em>. The equation of reaction is given below:

CaO + H₂O ----> Ca(OH)₂

The quantity of heat given off, ΔH°rxn = 64.8KJ/mol = 64800J/mol

Number of moles of CaO = mass/molar mass, where molar mass of Ca0 = 56g/mol, mass of CaO = 10.1g

Number of moles of CaO = 10.1g/56g/mol =0.179moles

Quantity of heat given off by 0.179 moles = 64800 *0.179 = 11599.2J/mol

Using the formula, <em>Quantity of heat, q = mass * specific heat capacity * temperature rise.</em>

mass of mixture = (10.1 + 157)g = 167.1g, Initial temperature = 18.0°C

Final temperature(T₂) - Initial temperature(T₁) = Temperature rise

11599.2J/mol = 167.1g * 4.18J/g·°C * ( T₂ - 18.0°C)

11599.2 = 698.478T₂ - 12572.604

11599.2 + 12572.604 = 698.478T₂

698.478T₂ = 24171.804

T₂ = 34.6°C

Therefore, final temperature attained by water = 34.6°C

6 0

3 years ago

Write balanced chemical equation for the reactions used to prepare each of the following compounds from the given starting mater

creativ13 [48]

Explanation:

A balanced chemical equation is defined as the one that contains same number of atoms on both reactant and product side.

Whereas a chemical reaction that brings change in oxidation state of the reacting species is known as a redox reaction.

When there occurs decrease in oxidation number of an element then it shows the element has been reduced. And, if there occurs an increase in oxidation state of an element then it means the element has been oxidized.

(a) The reaction between nitrogen and hydrogen to form ammonia will be as follows.

$N_{2} + 3H_{2} \rightarrow 2NH_{3}$

So here, oxidation state of nitrogen is changing from 0 to -3. Whereas oxidation state of hydrogen is changing from 0 to +3.

Reaction between ammonia and nitric acid will be as follows.

$NH_{3} + HNO_{3} \rightarrow NH_{4}NO_{3}$

Since, it is a combination reaction. Therefore, no change in oxidation state of reacting species is taking place.

(b) Reaction for conversion of liquid bromine to hydrogen bromide is as follows.

$H_{2}(g) + Br_{2}(l) \rightarrow 2HBr(g)$

Here, oxidation state of hydrogen is changing from 0 to +1. Therefore, oxidation of hydrogen is taking place. On the other hand, oxidation state of bromine is changing from zero to -1. Therefore, reduction of bromine is taking place.

(c) Reaction between Zn and S will be as follows.

$Zn(s) + S(s) \rightarrow ZnS(s)$

Here, oxidation state of zinc is changing from 0 to +2. Hence, oxidation of zinc is taking place.

Oxidation state of sulfur is changing from 0 to -2. Therefore, reduction of sulfur is taking place.

7 0

3 years ago

3. What should you do after an earthquake when you are in a building?

balu736 [363]

Answer:

3. You should walk fast in moving out.

4. You should stay in the evacuation center. Avoid going back to your car, aftershocks may occur.

5. Do not run

7 0

2 years ago

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