Summary
1.
Water is the most abundant substance on the surface of the earth.
About 71% of the earth's surface is covered by water.
2. Hydrogen is prepared in the laboratory by the action of zinc on
dilute hydrochloric acid or dilute sulphuric (VI) acid.
3. Hydrogen burns in oxygen to produce water. Water is an oxide
of hydrogen.
4. Active metals react with cold water to produce hydrogen gas
and the hydroxide of the metal in solution. Less active metals
react with steam to produce hydrogen and the oxide of the metal.
Copper and lead do not react with water.
5. Hydrogen is a reducing agent. It removes combined oxygen
from metal oxides of the less reactive metals.
6.
Reduction is the loss of oxygen from a compound. Oxidation is
the gain of oxygen by a substance.
7.
A reducing agent is a substance which removes oxygen from
another substance. An oxidising agent is a substance which gives
out oxygen to another substance.
when
water changes the
colour of coppe - 11
Revision Exercise sulphatorom blueto
1. (a) State the chemical tests for presence of water.
water change the color
(b) State the test, which is used to show that water is pure. Chistide paper from b
of copper anhydrous cobele
2.
Describe an experiment to show that water is an oxide of hydrogen.t non
3. State the precautions that must be taken when carrying out experiments with hydrogen.
Why is it not advisable to use iron in making steam boilers?
Write a word equation for a reaction in which hydrogen acts as a reducing agent.
Name the products formed when kerosene is burned in air.
State what is observed when a small piece of potassium is placed in water. Write a
word equation for the reaction.
Draw a labelled diagram to show how a reaction between steam and magnesium should
be carried out.
Describe how dry hydrogen is prepared in the laboratory.
Property of the Government of Kenya
Potassium
sodium
Calcim
Magne
Alun
Corbi
Zin​

Answer:

43.1atm is the pressure using gas law and 27.2atm using Van der Waals Law.

Explanation:

Ideal gas law is:

PV = nRT

Where P is pressure in atm

V is volume = 4.00L

n are moles of the gas (For chlorine Molar Mass: 70.90g/mol):

500g * (1mol / 70.90g) = 7.052 moles

R is gas constant = 0.082atmL/molK

T is absolute temperature = 25°C + 273 = 298K

To solve the pressure, P:

P = nRT/V

P = 7.052mol*0.082atmL/molK*298K / 4.00L

P = 43.1atm is the pressure using gas law.

Van der Waals equation is:

[tex]P + a(\frac{n}{V})^2 * (V-nb) = nRT[/tex]

Where a is 6.58L²atm*mol⁻²

b = 0.056Lmol⁻²

Solving for pressure:

[tex]P + a(\frac{n}{V})^2 = \frac{nRT}{(V-nb)}[/tex]

[tex]P = \frac{nRT}{(V-nb)}-a(\frac{n}{V})^2[/tex]

[tex]P = \frac{7.052mol*0.082atmL/molK*298K}{(4.00L-7.052mol*0.056L*mol)}-6.58L^2mol^{-2}(\frac{7.052mol}{4.00L})^2[/tex]

P = 172.323 / 3.6051 - 20.4866

P = 27.2atm using Van der Waals Law

Answer:

214

Explanation:

Q=mco

Q=heat

M is mass

C is specific heat

O is increased in temperature

Answer:

0.0898M is the molarity of the basic solution

Explanation:

The reaction of calcium hydroxide, Ca(OH)₂ with H₃PO₄ is:

3 Ca(OH)₂ + 2 H₃PO₄ → 6H₂O + Ca₃(PO₄)₂

To solve this question we must find the moles of H3PO4 that react. With the moles and the rection we can find the moles of Ca(OH)2. Using its volume we can find its molarity:

Moles H3PO4:

0.0189L * (0.200mol / L) = 0.00378 moles H3PO4

Moles Ca(OH)2:

0.00378 moles H3PO4 * (3mol Ca(OH)2 / 2mol H3PO4) = 0.00567 moles Ca(OH)2

Molarity:

0.00567 moles Ca(OH)2 / 0.06315L =

Answer:

Conductors

Explanation:

If the temperature of a gas inside a flexible container with a volume of 50 liters (L) decreases from 500°C to 100°C, then new volume will be 10L.

Volume and temperature of the gas is directly proportional to each other and for this question, equation becomes,

V₁/T₁ = V₂/T₂, where

V₁ = initial volume = 50L

T₁ = initial temperature = 500°C

V₂ = final volume = ?

T₂ = final temperature = 100°C

On putting values, we get

V₂ = (50)(100) / (500) = 10L

Hence required volume of gas is 10L.

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Answer: B) The half-life of Co-57 is 10 days

D) After twenty days have elapsed, about 25% of the Co-57 remains.

E) Scientists have an 8 gram sample of Co-57. After thirty days, 1 gram remains.

Explanation:

Answer: the answer is 35.6

Explanation:

Look up the answer but take out you must show all your work and resources should pop up I’m on the same question now for chemistry so I’m putting 35.6L

Answer:

Freezing of water

Explanation:

When water becomes a solid it releases heat into its surroundings (warming it up).

Answer:

get what right?

Answer:

You didn't post the question.

Explanation:

Edit your question and I'll try to help you.

Hope this helped? Lol.

Answer:

lets be honest

Explanation:

no one knows and this is worthless to answer for the worth of 5 points

zero kelvin, or minus 459.67 degrees Fahrenheit (minus 273.15 degrees Celsius)

Answer:

Yes, oil is a non renewable energy source

Explanation:

Because once these resources are used up, they cannot be replaced.

Answer:

yes its a nonrenewable resource because once you use it you cant put it back

Explanation:

Answer:

Water has a very high heat capacity, which makes it useful for radiators ... the temperature change that a given substance will undergo when it is either heated or cooled. ... The heat that is either absorbed or released is measured in joules. ... A 15.0 g piece of cadmium metal absorbs 134 J of heat while rising from 24.0°C to ...

Answer:

orange

0.8

Explanation:

On egde

Acturus which is a star   with surface temperature 4290 K is orange in color and has a mass of 0.8 kilograms.

A star is an astronomical object comprising a luminous spheroid of plasma held together by self-gravity. The nearest star to Earth is the Sun. Many other stars are visible to the  eye at night, but their immense distances from Earth make them appear as fixed points of light. The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names.

Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. The observable universe contains an estimated 1022 to 1024 stars.A star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements.

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Answer:

b)sugar and water : Sedementation

d) salt and water : evaporation

Answer: During a phase change, such as melting or boiling, the kinetic energy increases.

Explanation:

Kinetic energy is the energy obtained by the molecules of a substance due to their motion.

When phase change such as melting or boiling takes place then it means heat is absorbed by the substance. As a result, their molecules more even more rapidly from one place to another due to which more number of collisions take place.

Hence, a change in phase of substance occurs as kinetic energy increases in melting or boiling process.

Thus, we can conclude that during a phase change, such as melting or boiling, the kinetic energy increases.

Answer:

A It changes shape and volume

Explanation:If a liquid turns into a gas it starts to change shape since they are not the same

Answer:I believe it’s A

Explanation:when a liquid turns into a gas it the volume increases of the substance and of course the shape changes

Answer:

i think the second answer " fish migration might be prevented" might possibly be your answer

Answer:

The moons gravitational pull on Earth

Explanation:

Regarding non-GHG environmental impacts, research suggests that production of biofuel feedstocks, particularly food crops like corn and soy, could increase water pollution from nutrients, pesticides, and sediment (NRC 2011). Increases in irrigation and ethanol refining could deplete aquifers (NRC 2011).Regarding non-GHG environmental impacts, research suggests that production of biofuel feedstocks, particularly food crops like corn and soy, could increase water pollution from nutrients, pesticides, and sediment (NRC 2011). Increases in irrigation and ethanol refining could deplete aquifers (NRC 2011)

Answer:

divide the distance by the average

Explanation:

ash QC ok

Answer: 6

Explanation: 2*3=6

Answer:

I dont understand what is the question you need help on-

Explanation: