Can you help me pretty please !!!

Answer:

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Food webs can be used to study bottom-up or top-down control of community structure.

Explanation:

Food chains are important because they show the intricate relationships in ecosystems. They can reveal how each organism depends on someone else for survival. Food chains also display what happens when a problem occurs and a producer or consumer is lost.

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Answer:

K2 Cr2 O7 is the empirical formula

Explanation:

Assume we have 100 g of the compound, because it makes the number of grams equal to the percentage.

Then convert grams of each element into moles

Then divide the moles of each element by the smallest number of moles attained to get the whole number mole ratios of the empirical formula

However, if you don't get whole numbers when you divide by the smallest number of moles, then multiply all moles by one common factor that  makes them all whole numbers.

Answer:

A free body diagram is used to calculate static and dynamic forces acting on an object. In other words, a free body diagram is the starting point to develop a mathematical model to find and calculate various forces acting on a body.

Explanation:

Answer:

qns-4

1-multicellular organism

2-unicellular organism

3-unicellular organism

4-multicellular organism

5-unicellular organism

6-multicellular organism

7-unicellular organism

Answer:

no

Explanation:

The term mole concept is used here to determine the moles of ammonia. The number of moles of ammonia which can be make from 6.20 moles of N₂ is 12.4.

One mole of a substance is defined as that quantity of it which contains as many entities as there are atoms exactly in 12 g of carbon - 12. The formula used to calculate the number of moles is:

Number of moles = Given mass / Molar mass

You need one nitrogen atom to produce ammonia. Here we can see that there are two nitrogen atoms in N₂.

One mole of any substance contains Avogadro number of molecules. A mole is defined as the mass of the substance which consists of the equal quantity of basic units.

The number of moles of ammonia from 6.20 moles of N₂ is:

6.20 × 2 = 12.4

Thus the number of moles is 12.4.

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Answer:

technology is a silent factor

Explanation:

learned about it in computer class.

Answer:

SO₄⁻² (aq)  +  Mg²⁺ (aq)  ⇄  MgSO₄ (s) ↓

Precipitation reaction

Explanation:

Mg²⁻ is one of the metals at group 2 in the Perodic Table. This group is called, the alkaline earth metals.

To make precipitate the Mg²⁺ we can use a salt of sulfate, either flouride or phosphate. Those are three salts that can precipitate this metal.

We use sodium as cathion so, first of all we dissociate them:

Na₂SO₄ (aq) →  2Na⁺  (aq)  +  SO₄⁻² (aq)

NaF (aq) →  Na⁺ (aq) +  F⁻ (aq)

Na₃PO₄ (aq) →  3Na⁺ (aq)  +  PO₄⁻³ (aq)

In all cases, the reaction is of the precipitation type and is conditioned by the Kps, the solubility product constant. Let's bond the anions with Mg²⁺.

SO₄⁻² (aq)  +  Mg²⁺ (aq)  ⇄  MgSO₄ (s) ↓    Kps

2F⁻ (aq)  +  Mg²⁺ (aq)  ⇄   MgF₂ (s) ↓      Kps

2PO₄⁻³ (aq)  +  3Mg²⁺ (aq)  ⇄  Mg₃PO₄ (s) ↓   Kps  

How much energy is required to raise the temperature of 3 kg of aluminum from 18°C to 23°C? Use the table below and this equation: Q=mcΔT

Balanced Eqn

2

C

2

H

6

+

7

O

2

=

4

C

O

2

+

6

H

2

O

By the Balanced eqn

60g ethane requires 7x32= 224g oxygen

here ethane is in excess.oxygen will be fully consumed

hence

300g oxygen will consume  

60

⋅

300

224

=

80.36

g

ethane

leaving (270-80.36)= 189.64 g ethane.

By the Balanced eqn

60g ethane produces 4x44 g CO2

hence amount of CO2 produced =

4

⋅

44

⋅

80.36

60

=

235.72

g

and its no. of moles will be  

235.72

44

=5.36 where 44 is the molar mass of Carbon dioxide

hope this helps

Answer:

Ethane Combustion Reaction or just  Combustion Reaction

Explanation:

Answer:

A cell's plasma membrane, also known as the cell membrane, provides protection. It also maintains a constant atmosphere within the cell, and the membrane serves a variety of purposes. The first is to transport nutrients into the cell, and the second is to transport toxic compounds out

Explanation:

Answer:

answer 3

Explanation:

Answer:

It's the 4th one. waves are created by the wind

Answer:

C. Ocean waves form as wind moves across the surface, transferring its energy to the water.

Explanation:

hope this helps! c:

Answer:

Percent yield = 7.1%

Explanation:

The general reaction of the problem is:

Ca(OH)₂ + CO₂ → H₂O + CaCO₃

To solve this question we need to find theoretical yield using the amount of carbon dioxide added because:

Percent yield = Actual yield (3.22g) / Theoretical yield * 100

Theoretical yield is the maximum amount of product that could be obtained. To find it we need to convert the mass of CO₂ to moles. The moles of CO₂ = Moles of CaCO₃:

Moles CO₂ -Molar mass: 44.01g/mol):

20.0g * (1mol / 44.01g) = 0.454 moles CO₂ = Moles of CaCO₃ produced

Mass CaCO₃ = Theoretical yield -Molar mass: 100.09g/mol-:

0.454 moles * (100.09g / mol) = 45.5g of CaCO₃ = Theoretical yield.

Replacing:

Percent yield = 3.22g / 45.5g * 100

Answer:

The particles need energy to overcome the attractions between them. As the liquid gets warmer more particles have sufficient energy to escape from the liquid. Eventually even particles in the middle of the liquid form bubbles of gas in the liquid.

Answer:

I think it is Organ

Explanation:

Answer: A. dipole

Explanation:

Dipole can be defined as the separation of the equal and opposite charges present in the molecule via ionic bonding. The water molecule comprising of two molecules of hydrogen being positively charged and one molecule of oxygen being negatively charged are connected via ionic bonding thus water molecule is an example of dipole molecule. There is unequal distribution of the electrical density throughout the molecule.

The polar molecule results in a dipole when equal but opposite charges are present in two regions.

Dipole:  

Dipole arises when a molecule have opposite and equal charge in the ends.

For example - water molecule

In water molecule Oxygen is negatively charged and hydrogen have low electronegativity, this difference in electronegativities arise dipole in molecule.

Therefore, the polar molecule results in a dipole when equal but opposite charges are present in two regions.

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Answer:

7.67

Explanation:

According to molar concentration, the molarity of solution which contains 22.41 grams of NaCl in 50.0 ml of solution is 7.67 M.

Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.

The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.

In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.Substitution of values in the given formula gives, molarity= 22.41/58.44×1/0.05=7.67 M.

Thus, the  molarity of solution which contains 22.41 grams of NaCl in 50.0 ml of solution is 7.67 M.

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Answer:

C:Rainwater dissolves minerals out of the rocks and soil along the stream during runoff

Answer:

-2 , -1

Explanation:

H2PO4=-1

+1 × 2 + +5 + 4 ×O=-1

7+ 4O =-1

4O= -8

O = -2

H2O2=0

+1 × 2 +2 x O =0

2 + 2O=0

O= -1

(As the oxidation number of Hydrogen is +1 , and we have 2 hydrogen atoms so we multiply by 2 , while the oxidation number of P is +5 in this equation, also the compound as a whole equals -1 , then we do the steps as followed)

(while the other compound as a whole equals zero , and doing steps as followed)

*if anything is unclear send me a message*

Answer:

0.119 moles

Explanation:

molar mass of Fe = 55.845g

to find moles = mass/ molar mass

so moles of Fe = 20/55.845

= 0.358 moles

for the equation you are given

for every three Fe, it produces 1 Fe3O4 , meaning the ratio is 3:1

if you have 0.358 moles of Fe, that means the number of moles of Fe3O4  will equal to one third of that,

thus

moles of Fe3O4 = 1/3 x 0.358 = 0.119

Answer:

An element contains just one type of atom. A compound contains two or more different atoms joined together. A mixture contains two or more different substances that are only physically joined together, not chemically. A mixture can contain both elements and compounds.

Answer:

"1. buoyant or suspended in water or air.

2.not settled in a definite place; fluctuating or variable."

Explanation:

Hope this helps! :)