Question 2 (1 point)
Which of the following does NOT involve a chemical reaction?
Fallen leaves decay in a compost pile.
Leaves change color in the fall.
O A fire burns a pile of fallen leaves.
A pond freezes over in the winter.

Answer:

the percentage composition of mass of nitrogen in NH OH is 42.86 %

Answer:

Answer is B

Explanation:

It's not A because we're boiling only water.

It's not C because the last dot for 2 cups ends at 70 min while the last dot for 4 cups ends at 90 min.

It's not D because water boils at around 100 C, as shown in the graph. The highest dot for both 2 cups and 4 cups were about the same near 100 C.

The graph shows that 4 cups of water is able to retain heat more (higher heat capacity), so it takes more time for water to cool down than 2 cups of water.

Answer:

A. When two aqueous solutions are mixed, a precipitate is formed.

Explanation:

The precipitate (a solid substance that falls from the liquid) is the result of a chemical reaction taking place between the liquids.

The other three answer choices are indicative of physical changes (temperature change, phase change, color change).

When two aqueous solutions are mixed, a precipitate is formed indicates that a chemical change has occurred.  

Hence, option A is correct answer.

Chemical change are those changes in which substance changes chemical composition. These changes are permanent changes. In chemical change new substances formed and in chemical change substances can not get back into its original form. It is irreversible change.

Physical changes are those changes in which substance changes physical properties only. Properties like temperature, pressure, shape, color, size, state (solid, liquid and gas). These changes are temporary in nature. In physical change no new substances formed. It is reversible change.

Now, check all the options one by one:

Option (A): When two aqueous solutions are mixed, a precipitate is formed is a chemical change. Since precipitation indicate a chemical reaction (that is double displacement reaction).

Option (B): As ammonium nitrate dissolved in water causes the temperature to decrease is a physical change because heat energy is absorbed here and it is a endothermic reaction.

Option (C): Alcohol evaporates when left in an open container is a physical change because evaporation is a physical change as it changes the state from liquid state to gas state.

Option (D): Water is added to blue copper (II) chloride solution. The resulting mixture if lighter blue in color is a physical change as properties like change in color is physical change.  

Thus, from above conclusion we can say that When two aqueous solutions are mixed, a precipitate is formed indicates that a chemical change has occurred.  

Hence, option A is correct answer.

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Answer:

2) 0.4 mol

Explanation:

Step 1: Given data

Step 2: Convert "V" to L

We will use the conversion factor 1 L = 1000 mL.

500 mL × 1 L/1000 mL = 0.500 L

Step 3: Calculate the moles of KBr (solute)

The molarity is the quotient between the moles of solute (n) and the liters of solution.

M = n/V

n = M × V

n = 0.8 mol/L × 0.500 L = 0.4 mol

Answer:

1- veins

2-aorta

3-valve

4-ventricles

5-atrium

Answer:

77.81 g of CuNO₃

Explanation:

6 CuNO₃  +  Al₂(SO₄)₃  ⇒  3 Cu₂SO₄  +  2 Al(NO₃)₃

This is your chemical equation.  We will need this information for converting from Al(NO₃)₃ to CuNO₃.

First, convert grams of Al(NO₃)₃ into moles using the molar mass.

[tex]44.0g*\frac{mol}{213.01g} = 0.2065mol[/tex]

Next, convert moles of Al(NO₃)₃ to moles of CuNO₃.  You can do this by using the stoichiometry (the numbers in front of the compounds).  For every 6 moles of CuNO₃, you will get 2 moles of Al(NO₃)₃, causing the ratio of CuNO₃ to Al(NO₃)₃ to be 6:2.

[tex]0.2065mol*\frac{6}{2} =0.6197mol[/tex]

Now that you moles of CuNO₃, convert this to grams using its molar mass.

[tex]0.6197 mol * \frac{125.56g}{mol} =77.81 g[/tex]

You will need 77.81 grams of CuNO₃ to produce 44.0 grams of Al(NO₃)₃.

Answer: Polarity, Boiling and Freezing Points, Specific Heat Capacity, Density, Surface Tension, Heat of Vaporization and Vapor Pressure, Capillary Action, Solid State (Ice), Liquid State (Liquid Water), Gas State (Steam),  

Explanation:  Water molecules are polar, so they form hydrogen bonds. This gives water unique properties, such as a relatively high boiling point, high specific heat, cohesion, adhesion, and density.

Answer:

molar mass of H2CO3 = 72.0228

Answer:

62.02 g/mol

Explanation:

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Answer:

[NaCl(aq)] = 0.25M

Explanation:

Molarity = moles solute / volume of solution in liters

moles NaCl in 29.25 grams = 29.25g/58g·mol⁻¹ = 0.5043 mole

Molarity = 0.5043 mole NaCl / 2 Liters = 0.2555M ≅ 0.25M (2 sig-figs)

Answer:

True

Explanation:

Answer: true

Explanation:

Thermal efficiency of process heating equipment

Answer:

2 N

Explanation:

Answer:

513.975g

Explanation:

I'm assuming that the question has Aluminium and Chlorine as the question is not clear.

1. Balance the equation

  2 Al + 3 Cl2  → 2AlCl3

2. Use the mole = mass/mr equation and molar ratio to find the mass of AlCl3

   133.5 x 3.85 = 513.975g

Answer:

Explanation:

A graduated cylinder was filled to 30.0 mL with a liquid. An unknown metal cylinder having a mass of 60.27 g was submerged in the in the liquid. The final volume of the liquid level was 45.2 mL.

a. Calculate the density of the unknown metal cylinder.

b. The density of the liquid is 0.899 g/mL. What is the mass of the liquid in the graduated cylinder?

Answer: A> B> C > D> E

Explanation:

pH or pOH is the measure of acidity or alkalinity of a solution.

pH is calculated by taking negative logarithm of hydrogen ion concentration.

[tex]pH=-\log [H^+][/tex]

a) Solution A: pH =2  

[tex][H^+]=10^{-2}[/tex]

b) Solution B: pH =5  

[tex][H^+]=10^{-5}[/tex]

c) Solution C: pH = 7  

[tex][H^+]=10^{-7}[/tex]

d) Solution D: pH = 8  

[tex][H^+]=10^{-8}[/tex]

e) Solution E: pH =13

[tex][H^+]=10^{-13}[/tex]

Thus the decreasing order of hydrogen ion concentration is A> B> C > D> E

Answer:

the scientific name is Angiosperms

Explanation:

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Answer:

1.used to seperate solids from liquids, and is a act of pouring a mixture onto a membrane this allows the passage of liquid and results in the collection of a solid

2. the solution would passed through without losing and solids

3 would allow them to dry or on further hearing decompose

Explanation:

Answer: The coefficients are 2, 2 and 1.

Explanation: According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants.

The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

The balanced chemical equation for the given reaction is:

2H2o➡️2h2+o2

Solution :

For the reaction given :

[tex]$\text{2Hg}_{(l)}+\text{O}_2_{(g)} \rightarrow \text{2HgO}_{(s)}$[/tex]

Thus we know that the equilibrium constant [tex]$K_c$[/tex] contains aqueous an dgas species only.

∴       [tex]$K_c=\frac{1}{[O_2]}$[/tex]    ............(1)

Now at the equilibrium, an amount of the 13.4 g of oxygen was found in the vessel of 6.9 liters. For determining the concentration of the oxygen gas, we use :

[tex]$[O_2]= \frac{n_{O_2}}{V_{soln}}$[/tex]  ...................  (2)

Here, [tex]$n_{O_2}$[/tex] = no. of moles of oxygen gas (mol)

         [tex]$V_{soln}$[/tex] = volume of solution (L)

Therefore the number of moles of the oxygen gas is calculated by directly using the molecular weight (31.9988 g/mol) as the conversion factor.

∴      [tex]$n_{O_2}= 13.4 \ g \times \frac{\text{1 mol}}{31.9988 \ g}$[/tex]

              = 0.418 mol

Now substituting the known values in (2), we can find the equilibrium concentration of the oxygen gas :

[tex]$[O_2] =\frac{0.418 \ \text{mol}}{6.9 \ \text{L}}$[/tex]

     = 0.0605 M

Therefore substituting the result in (1), the equilibrium constant for the reaction is :

[tex]$K_c=\frac{1}{0.0605}$[/tex]

    = 16.52

Answer:

2 no. is the answer surface currents that move in a path opposite to the wind currents

Answer:

no.2 is the answer of your question

Answer:

Mass

Explanation:

Answer:

5.916x10⁻³ mol OH⁻

Explanation:

The reaction that takes place is:

First we calculate the added moles of each reagent, using the given volumes and concentrations:

Now we calculate how many KOH moles reacted with 3.967 mmol H₂SO₄:

Finally we calculate how many OH⁻ moles remained after the reaction

Answer:

73.2 pm

Explanation:

"The anions make contact along the diagonal of the face of the unit cell, so the diagonal of the face is equal to 4 ionic anion radii. By letting r represent the ionic radius of the anion, d represent the diagonal of the face of the unit cell, and x represent the edge length, then d=4r and

d^2=x^2+x^2=  2x^2

By substituting 4r for d, the second equation becomes

(4r)^2=(2)x^2

Solving this equation for r shows that

r=(x–√2)/4

Since the edge length x is 207 pm, the ionic radius of the anion is

r= ((207 pm) X [tex]\sqrt{2}[/tex])/4=73.2 pm

Notice that the formulae used to describe atomic radii include constants with exact values. Therefore, these values do not constrain the number of significant figures."

The ionic radius of the anion in the FCC unit cell where anions are in contact along the diagonal of the face of the unit cell is 73.1pm.

Ionic radius is the distance between the center of the atom and the outermost part.

As in the question it is given that anions are in contact along the diagonal of the face of the unit cell, so the length of the diagonal is represented as: d = 4r, where

r = ionic radius

Length of edge i.e. a = 207 pm (given)

Two adjacent edges and diagonal of a FCC unit cell makes a right angle triangle, by using pythagoras theorem we can write as:

a² + a² = d²

2a² = (4r)²

2a²/16 = r²

2(207)²/16 = r²

85,698/16 =  r²

0r r = 73.18 pm

Hence, 73.18 pm is the ionic radius of the anion.

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Answer: A person engaged in the practice of anthropology. Anthropology is the study of aspects of humans within past and present societies. Social anthropology, cultural anthropology and philosophical anthropology study the norms and values of societies.

Explanation: I HOPE THIS HELPS U AND ANSWERS UR QUESTION!!! Stay safe and healthy!

Answer:

your finger becomes negatively charged

Explanation:

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Answer:

I think it is copper

Explanation:

.........................

Answer:

copper

Explanation: