Which sample is a pure substance? zinc oxide sugar dissolved in water pond water soil

ΔH for this reaction : -2668.4 (exothermic)

The change in enthalpy in the formation of 1 mole of the elements is called enthalpy of formation  

The enthalpy of formation measured in standard conditions (25 ° C, 1 atm) is called the standard enthalpy of formation (ΔHf °)  

(ΔH) can be positive (endothermic = requires heat) or negative (exothermic = releasing heat)  

The value of ° H ° can be calculated from the change in enthalpy of standard formation:  

∆H ° rxn = ∑n ∆Hf ° (product) - ∑n ∆Hf ° (reactants)  

you can search the value of ΔHf on the internet

∆H ° rxn =( ∆H Al₂O₃+∆H AlCl₃+3.∆H NO + 6.∆H H₂O)-(∆H Al+∆H NH₄ClO₄)

[tex]\tt \Delta H^o~rxn=(-1669.8+-704+(3\times 90.4)+(6.\times -241.8)-(3\times 0+3\times -295)\\\\\Delta H6o~rxn=-3553.4+885=-2668.4~kJ/mol[/tex]

Answer:

2.3 * 1,000 = 2,300

Explanation:

The answer to this is true.

Answer:

Pressure decreases with increasing altitude

Explanation:

At higher elevations, there are less air moecules.

Explanation:

The pressure exerted by the air in the atmosphere is greatest at Earth's surface and falls as altitude increases. The reason is that density and depth of the atmosphere are greatest at sea level and decline with increasing altitude.

Answer:

no <3

Explanation:

Answer:

brody this aint the place for that daddy;)( no homo tho i aint with that gay stuff)

Explanation:

Answer:

so they can find the aswer and not get hurt

Explanation:

The scientist Neil Bohr has investigated the atom to be young and unattached to Albert Einstein thinking because he is fearless of his thinking and ready to find an explanation.

Einstein model is called as Einstein solid model. He stated as ever solid atom oscillate with the same frequency and contain large number of three dimensional quantum harmonic oscillation.

Bohr atomic model stated that electron revolve around the nucleus in its stable orbital without emitting radiant energy. It is primitive model of hydrogen atom. Bohr has given the expression l = nh / 2π

Where n = principle quantum number, l = angular momentum and h = plank constant

Thus, the scientist Neil Bohr has investigated the atom to be young and unattached to Albert Einstein thinking because he is fearless of his thinking and ready to find an explanation.

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Answer:

1. freshwater and marine.

2. Living parts of plants and animals

3. Only plants

4. Meats and plants

5. Meats

6. Other: (Anything they can find that's edible)

7. Break down dead plants and animals into nutrients

8. Prey

9. Rainfall

10. Deserts

Let me know if this helped! Have a nice day! Tell me if these are correct and if any are wrong!

Answer:

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\[/tex]

From the question we have

[tex]density = \frac{23.73}{3.0} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

the one with less thermal energy

Explanation:

thermal energy is heat

Answer:

GOTTTEM

Explanation:

Answer:

Do you want someone to go through and answer all of these questions??

Explanation:

I am on the dox, but idk if I could finish it fast enough to put the link in here. Is there a way to delete answers?

Cl2 + 2RbI → 2RbCl + I2  is possible while I2 + NiBr2 → NiI2 + Br2 is not possible.

It will do us a lot of good to write out the equations again;

Cl2 + 2RbI → 2RbCl + I2       Yes

I2 + NiBr2 → NiI2 + Br2         No

If we look at the reaction closely, they are displacement reactions. It is worthy to note that a specie can only displace another specie which lies below it in the activity series. The activity series is an arrangement of elements in order of decreasing reactivity.

The activity series of the halogens is; fluorine > chlorine > bromine > iodine.

Since chlorine is above iodine in the activity series, Cl2 + 2RbI → 2RbCl + I2 is possible.

Iodine is less than bromine in the activity series hence the reaction  I2 + NiBr2 → NiI2 + Br2 is not possible.

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Answer:

Cl2 + 2RbI --> 2RbCl + I2 = yes

I2 + NiBr2 --> NiI2 + Br2 = no

Explanation:

I just took the assinment

Nice written.

Is it written by you yourself or you have copied it from somewhere?

Answer:2:saturated

3:it got darker

4:it halved/unsaturated

Explanation:

Answer:

Answer:2:saturated

3:it got darker

4:it halved/unsaturated

Explanation:

Answer:

1.33 × 10²⁴ molecules CO₂

General Formulas and Concepts:

Chemistry - Stoichiometry

Explanation:

Step 1: Define

97.3 g CO₂

Step 2: Define conversions

Avogadro's Number

Molar Mass of C - 12.01 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of CO₂ - 12.01 + 2(16.00) = 44.01 g/mol

Step 3: Convert

[tex]97.3 \ g \ CO_2(\frac{1 \ mol \ CO_2}{44.01 \ g \ CO_2} )(\frac{6.022 \cdot 10^{23} \ molecules \ CO_2}{1 \ mol \ CO_2} )[/tex] = 1.33138 × 10²⁴ molecules CO₂

Step 4: Check

We are given 3 sig figs. Follow sig fig rules.

1.33138 × 10²⁴ molecules CO₂ ≈ 1.33 × 10²⁴ molecules CO₂

Answer:

3 we have three states of matter

Answer:

We have THREE (3) states of matter namely;

*Solid state

*Liquid state

*Gaseous state

Answer:

it is false it cannot be a model

Answer:

A

Explanation:

Hopefully this helps

What, if anything, is wrong with the nuclear equation shown below?

a. the daughter product has the wrong atomic number.

b. The daughter product has the wrong mass number.

c. The particle labeled "e" should have a mass number of 1.

d. There is nothing wrong with the equation.

Answer:

a. the daughter product has the wrong atomic number.

Answer: No, it is a rule. The aufbau principle, from the German Aufbauprinzip, also called the aufbau rule, states that in the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels. For example, the 1s subshell is filled before the 2s subshell is occupied.

Answer:

28g

Explanation:

Given parameters:

Number of moles of hydrogen  = 3moles

Unknown:

Mass of nitrogen used = ?

Solution:

 To solve this problem, let us establish the balanced reaction equation first;

             N₂  + 3H₂ →  2NH₃

From the balanced reaction equation;

                 3 mole of H₂ will combine with 1 mole of N₂

Now,

   Mass of Nitrogen  = number of moles x molar mass

         Molar mass of N₂  = 2(14) = 28g/mol

   Mass of Nitrogen  = 1 mole x 28g/mole  = 28g

Answer:

If we have more protons in the nucleus, then they hold it tighter

Answer:

Percent yield =  57%

Explanation:

Given data:

Mass of nitrogen = 15.0 g

Mass of hydrogen = 15.0 g

Mass of ammonia produced = 10.5 g

Percent yield = ?

Solution:

Chemical equation:

N₂+ 3H₂      →   2NH₃

Number of moles of hydrogen:

Number of moles = mass/molar mass

Number of moles = 15.0 g/ 2 g/mol

Number of moles = 7.5 mol

Number of moles of nitrogen:

Number of moles = mass/molar mass

Number of moles = 15.0 g/ 28 g/mol

Number of moles = 0.54 mol

Now we will compare the moles of ammonia with nitrogen and hydrogen from balance chemical equation.

              N₂       :        NH₃

               1         :          2

           0.54       :     2×0.54 = 1.08

             H₂         :           NH₃

              3           :            2

              7.5        :      2/3×7.5= 5 mol

Theoretical yield of ammonia:

Mass = number of moles × molar mass

Mass = 1.08 × 17 g/mol

Mass = 18.36 g

Percent yield:

Percent yield = (actual yield / theoretical yield) ×100

Percent yield = (10.5 g/ 18.36 g) ×100

Percent yield = 0.57 ×100

Percent yield =  57%

A moist red litmus paper is used for testing ammonia gas  because ammonia is a base which turns moist red litmus paper blue.

According to the Arrhenius concept, base is defined as a substance which yields hydroxyl ions on dissociation.These ions react with the hydrogen ions of acids to produce salt in an acid-base reaction.

Bases have a pH higher than seven as they yield hydroxyl ions on dissociation.They are soapy in touch and have a bitter taste.According to the Lowry-Bronsted concept, base is defined as a substance which accepts protons .Base react violently with acids to produce salts .Aqueous solutions of bases can be used to conduct electricity .They can also be used as indicators in acid-base titrations.

They are used in the manufacture of soaps,paper, bleaching powder.Calcium hydroxide ,a base is used to clean sulfur dioxide gas while magnesium hydroxide can be used as an antacid to cure acidity.

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Answer:

The charge an element would have if it lost or gained electrons

Answer:

-171.79 KJ

Explanation:

We must keep in mind that water freezes at 0 degrees centigrade

Recall that heat lost during freezing can be obtained from;

H = mc(θ2 - θ1)

m = mass of the water = 350 g/1000 = 0.35 Kg

c = specific heat capacity of water = 4,200 J/kg°C

θ2 = final temperature = 0°C

θ1 = initial temperature = 37°C

H= 0.35 * 4,200 * (0 - 37)

H = -54390 J = -54.39 KJ

Energy given out when 1 mole of water freezes at its freezing point = -6.04 kJ

For 350 g of water; 350 g/18 g/mol *  -6.04 kJ  = -117.4 kJ

Hence total energy removed = (-54.39 KJ) + (-117.4 kJ) = -171.79 KJ

Answer:

1. earth metal 2. halogen 3.The elements are arranged in seven horizontal rows, called periods or series, and 18 vertical columns, called groups. ... Elements in the periodic table are organized according to their properties.

Inventor: Dmitri Mendeleev please name most brainliest

Answer:

a: cells

Explanation:

just did it. your welcome have a nice day

answer :- The smallest unit of life that conducts all life function are cell

Answer: 1.91 moles

Explanation:

First you want to find the molar mass of NaCL

Na = 22.99g  Cl = 35.45g

22.99g + 35.45g = 54.44g

Then divide 111.5g by 54.44g and this will give you moles.

Answer:

When manganese(IV) oxide is added to hydrogen peroxide, bubbles of oxygen are given off. To make oxygen in the laboratory, hydrogen peroxide is poured into a conical flask containing some manganese(IV) oxide. The gas produced is collected in an upside-down gas jar filled with water.