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Answer: the equation for the reaction is NH4Cl (s) --> NH3 (g) + HCl (g)

equation for heat reaction:

ΔH25° = (ΔH25° NH3 + ΔH25° HCl) - ΔH25° NH4Cl)

question 2:

the 1st and 3rd reactions are better ontained through  refrence sources and the 2nd and 4th are the easiest and safest to measure in the laboratory. The 1st and rd reaction contains noxious gases this is because there is a (g) in both of the reactions. And the 2nd and 4th does NOT contain noxious gases so i assume its the safest to measure out in the lab  

Answer:

55.768

Explanation:

The following information is given in this question:

Fe-54 = 5.845%

Fe-56 = 91.754%

Fe-58 = 2.119%

First, we convert from percentage abundance to decimal abundance

Fe-54 = 5.845% = 0.05845

Fe-56 = 91.754% = 0.91754

Fe-58 = 2.119% = 0.02119

To find the average atomic mass of iron (Fe), we multiply each isotopes' decimal abundance by its mass no and find the sum as follows:

Average atomic mass = (0.05845 × 54) + (0.91754 × 56) + (0.02119 × 58)

Average atomic mass = 3.1563 + 51.38224 + 1.22902

Average atomic mass = 55.768

Answer:

The liquid left after crystallization is called Residue

Answer: According to the reactivity of metals Sodium is the second metal while Magneesium is the fourth metal. The metal in the top of the reactivity serise table are more reactive.

(The series obtained by the arrangement of metals in the decending oder of their  reactivity is the REACTIVITY SERIES TABLE)

Explanation:

K

Na

Ca

Mg

Al

Zn

Fe

Sn

Pb

H

Cu

Hg

Ag

Pt

Au

Therefore Sodium is more reactive than Magnesium

Answer:

The alkaline-earth metals tend to lose two electrons to form M 2+ ions (Be2+, Mg2+, Ca2+, and so on). These metals are less reactive than the neighboring alkali metal. Magnesium is less active than sodium; calcium is less active than potassium; and so on. These metals become more active as we go down the column.

Answer:

ns - time

12g/ml - density

1.8pm - length

250m2 - area

325K - temperature

5.4mL - volume

90kg - mass

Explanation:

The unit of measurement is used to identify what a measurement is. It is very important to place a specific unit for each measurement made as it distinguishes them from one another. In this question, various measurements were given, which can be identified using their units.

- ns is measurement for time because seconds (s) is its unit

- 12g/ml is measurement for density because grams/milliliters (g/mL) is its unit

- 1.8pm is measurement for length because length can be measured in picometer (pm).

- 250m2 is measurement for area because metre² (m²) is its unit.

- 325K is measurement for temperature because Kelvin is the absolute unit for temperature.

- 5.4mL is measurement for volume because volume can be measured in milliliters (ml).

- 90kg is measurement for Mass because kilograms (s) is its unit.

19. moth balls in the closet and observe after several days.

20. whenever wax or a candle burns it turns from solid to liquid but again at room temperature it turns to solid

21. evaporation, condensation, precipitation

22. it produces new substances

23. vinegar Bubbles when baking soda is added

24. steam

Answer:

A

Explanation:

becuase CaCI2 Is an inorganic compound

Answer:

From this solution, you can do the a number question answer.

Answer:

The correct answer is - at high pressure a huge amount of gases can be stored in less volume.

Explanation:

We already know that pressure is inversely proportional to the volume of gas which means if we increase the pressure the volume of gas becomes less.

P = 1/V

So in the scuba divers tank, the oxygen is filled at very high pressure so the high amount of the oxygen can be filled in less volume and which will last for longer than a normal pressure tank can last.

Answer:

the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product.

Answer:

the process by which green plants and some other organisms use sunlight to synthesize nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product.

A reaction in which reduction and oxidation take place simultaneously known as a redox reaction.

Answer:

all of this

Explanation:

Answer:

4.95L

Explanation:

Using Charle's law equation;

V1/T1 = V2/T2

Where;

V1 = initial volume (L)

V2 = final volume (L)

T1 = initial temperature (K)

T2 = final temperature (K)

According to the question, the following information was given:

V1 = 4.50L

V2 = ?

T1 = 27°C = 27 + 273 = 300K

T2 = 57°C = 57 + 273 = 330K

Using V1/T1 = V2/T2

4.50/300 = V2/330

Cross multiply

300 × V2 = 4.5 × 330

300V2 = 1485

V2 = 1485 ÷ 300

V2 = 4.95L

Answer:

Burning of fossil fuels

Explanation:

Human activities that increase the amount of carbon dioxide in the atmosphere are;

1) Burning of fossil fuels in industrial and  internal combustion engines

2) Depletion of the available forest cover, due to the consumption of wood as a raw material

3) Farming expansion  that lead to clearing of forests for farming

4) Industrial activities such as the production of cement

5) Deforestation to provide land for development including buildings and infrastructure.

Answer:

0.000256

Explanation:

Formula:

Divide the value volume by 1e+6

1 kl equal to 1000000ml

Answer:

câu trả lời trong hình ảnh

Answer:

3

Explanation:

The reaction for the extraction of Iron is :-

2Fe2O3(s) + 3C(s) → 4Fe(l) + 3CO2(g)

change in oxidation state (O.S.) = higher O.S - lower O.S

= 3 - 0

= 3

Answer:

Uses of iron

It is used to manufacture steel and also used in civil engineering like reinforced concrete, girders etc. Iron is used to make alloy steels like carbon steels with additives such as nickel, chromium, vanadium, tungsten, and manganese.

Answer:

iron is used to make water pipes.

used for making machines in industries.

used for making steam engine.

Answer:

Boiling, melting

Explanation:

Physical changes affect the form of a chemical substance.

Answer:

Im pretty sure its true

Explanation:

Answer:

answer is true .

Explanation:

this may help you

Explanation:

Activation energy is the minimum amount of energy required for a chemical reaction to take place.

When a chemical reaction occurs then bonds between the reactants break and bonds between the products are formed. This leads to the formation of an activated complex which is also known as transition state.

So, in order to form the activated complex a minimum amount of energy is necessary and this energy is known as activation energy.

Answer:

Diatomic molecules contain two atoms that are chemically bonded. If the two atoms are identical, as in, for example, the oxygen molecule (O2), they compose a homonuclear diatomic molecule, while if the atoms are different, as in the carbon monoxide molecule (CO), they make up…

Explanation:

yei hoo arko aaxaina ...

Answer:

E.....Na2I.,.

Explanation:

Cuz sodium has a Vallency..1......lodide has Vallency 2

Answer:

a gas at very low temperatures, when gas particles have very little kinetic energy

Explanation:

Answer:

B, C, and E!

Explanation:

got it correct on edge! :)

Answer:

1. False

2. True

3. False

4. False

5. True

6. False

7. True

8. True

9. True

Explanation:

I did it in steps to help u to understand :)

Answer: i dont know

Explanation: