₦airaland Forum

Good morning people..
I guess it's my off day today, neither biology nor agric ain't my thing. Nevertheless, I'm open to any question within my jurisdiction(math, Phy & chem)..
Have a great day guys

tuwayz:
Ok thank you sir

you're welcome bro

tuwayz:
Sounds like you are the tutor pls what about the last days at forcados high school how are we to get it?

you'll get that when you go for the registration at the cbt centres but you have to go along with the receipt which will be given to you at the bank

Elements, Mixtures and Compounds and Atoms and Molecules

A common question concerns the smallest identifiable units within elements, mixtures and compounds whose structure and properties explains the properties of the bulk material (element, mixture or compound).
Are they atoms or molecules, or something else ?

This can be answered in both words and diagrams. It often helps to include both.
More Advance Note: There are also even smaller units called "sub-atomic particles" which, together, form atoms.

Elements, Mixtures, Compounds - Atoms and Molecules

Do elements, mixtures and compounds consist of atoms or molecules ?

Answer in words:

Elements can consist of either atoms or molecules but if molecules then those molecules are formed only from atoms of the same type (that is, atoms of the same element).
For example, a molecule of oxygen consists of two atoms of oxygen and has the chemical formula O2 where "O" is the chemical symbol of the element oxygen.
Mixtures can consist of either atoms or molecules - but must include at least two different atoms or molecules.
For example, a mixture of neon and argon gases would consist of atoms only because both neon and argon exist as atoms rather than as molecules. However, a mixture of oxygen and nitrogen gases would consist only of molecules because oxygen gas exists as oxygen molecules (O2) and nitrogen gas exists as nitrogen molecules (N2). A mixture of neon and nitrogen gases would consist of atoms of neon and molecules of nitrogen.
Compounds consist only of molecules (not individual atoms) and all the molecules of any one compound are the same. For example, methane gas has the chemical formula CH4 because each molecule of methane is formed from one atom of carbon, whose chemical symbol is "C", and four atoms of hydrogen, whose chemical symbol is "H". Pure methane gas does not include any other atoms or molecules apart from the methane molecules described by the formula CH4.

This can be summarized in a table:


Atoms

Molecules
Elements


Either atoms or molecules, but only of one type of atom.
How do you know which it is ?
Solid elements, e.g. metals, consist of many atoms of the element packed very densely together, e.g. copper, whose symbol is "Cu". Only a few elements exist naturally as a liquid at standard temperature and pressure. An example is the metal mercury, whose symbol is "Hg", which takes the form of many atoms that can move around each other easily but not away from the other atoms into the surrounding space, as in the case of gases.
Many elements exist as a gas at standard temperature and pressure. In some cases, e.g. the inert or "noble" gases, the gas exists in the form of individual atoms, whereas in other cases the gas exists in the form of molecules (e.g. diatomic molecules - which means that each molecule is formed from two atoms of the the element, attached together), e.g. oxygen gas, whose formula is O2, nitrogen gas whose formula is N2 and hydrogen gas whose formula is H2.
Elemental gases exist as either atoms or molecules according to the size and structure of the atoms of that element - which is usually explained later in school chemistry lessons.

Mixtures
Any combination of (different) : atoms + atoms
or molecules + molecules
or atoms + molecules

That is, in the case of mixtures there must be at least two different types of atoms,
or at least two different types of molecules,
or at least one type of atom plus at least one type of molecule present.

So, a mixture of gases may consist of molecules of the element oxygen (O2) plus molecules of the element nitrogen (N2) plus molecules of the compound carbon dioxide (CO2).
Alternatively, a mixture of gases may consist of atoms of neon (Ne) and atoms of argon (Ar), and so on ...
Compounds

Compounds consist of only one type of molecule: A molecule is the smallest part of a compound whose properties are those of the compound.

Elements, Mixtures and Compounds

Chemistry is the study of physical matter, which is classified in many different ways, such as state of matter (gas, liquid or solid), chemical form (element, mixture or compound), chemical structure (atoms or molecules, etc.) and so on.

It is important to understand the terms "element", "mixture" and "compound", because these convey useful information.
Another useful term is the word "substance", which can be used to refer to either an element or a compound - but not to a mixture because a "substance" always has a definite composition. The most general term is "matter" which can be used to refer to any of "substances", "elements", "mixtures" or "compounds".

Elements Mixtures and Compounds

The categories of elements, mixtures and compounds are described in words below:
Elements
consist of only one type of atom - which may, or may not join together to form molecules or large structures, therefore:
can exist as either atoms (e.g. argon) or molecules (e.g., nitrogen)
cannot be broken down into a simpler type of matter by either physical or chemical techniques - though some larger elements break-down spontaneously due to being radioactive.

Elements are listed in the periodic table.

Many elements are found in nature and so may be called "naturally occurring elements". Other elements have not been found in nature but can be produced in the laboratory. A few more elements are thought to exist but are very rare and even if produced would only exist for a very short time because they are radioactive and would quickly decompose into other elements whose atoms are smaller.

Mixtures
consist of two or more different elements and/or compounds - physically intermingled,
can be separated into their constituent parts by physical means (e.g. distillation of liquids or separating magnetic and non-magnetic solids using a magnet), and
have many of the properties of their constituent parts (e.g. the element "oxygen" is part of the mixture "air" and some of the properties of air are due to the oxygen, albeit somewhat reduced compared with pure oxygen due to the presence of the other constituents of the mixture called "air".

There are many different types of mixtures, some of which have special names. These include:

Homogeneous Mixtures - in which the two or more substances that form the mixture are evenly distributed throughout the mixture, e.g. vinegar is a homogeneous mixture of ethanoic acid and water.
Heterogeneous Mixtures - in which the two or more substances that form the mixture are not evenly distributed throughout the mixture, e.g. oil and water.
Solutions - a special type of homogeneous mixtures in which one substance (called the "solute" is dissolved in another substance (called the "solvent", e.g. salt water is salt dissolved in water - in such a way that the salt no-longer exists as solid particles within the water.
Suspensions - heterogeneous fluid mixtures containing solid particles large enough for sedimentation, which means that the particles (compare with the "solute" part of a solution) will eventually settle to the bottom of the container (unlike in the case of colloids, below), e.g. particles of sand in water.
Colloids - heterogeneous mixtures in which one is substance microscopically dispersed evenly throughout another substance (for comparison, the size of the particles of "solute" are greater than in the case of a solution, but much smaller than in the case of a suspension). There are many naturally occurring colloids, e.g. milk. Colloids are very important in biology and medicine.
Alloys - mixtures in which the main element (or elements) are metal(s). A more technical definition of an alloy is "a partial or complete solid solution of one or more elements in a metallic matrix". Common examples of alloys include bronze, brass and steels.



Compounds

consist of atoms of two or more different elements bound together chemically,
can be broken down into a simpler type of matter (elements)
by chemical means; but not by physical means
always contains the same ratio of component atoms.
have properties different from their component elements (e.g. the compound water (H2O) is a liquid at room temperature and pressure and has different chemical properties from those of the two elements, hydrogen (H2) and oxygen (O2), from which it is formed).

A compound is a pure substance that consists of two or more elements chemically combined in a fixed proportion, that can be further subdivided into simpler substances by chemical (not physical) means only.
So, if a quantity of a material consists of atoms of two or more elements joined together, always in the same ratio, then the matter forming that material is a compound.

Compound whose molecules consist of one atom of one element chemically joined with two atoms of another element.

A molecule is the smallest part of a compound whose properties are those of the compound.
A compound can be represented by using a chemical formula.

tuwayz:
Bros where you given the syllabus at the bank? They collected my 5k but didn't give me brochure nor syllabus nor THE LAST DAYS AT FORCADOS HIGH SCHOOL, what am I suppose to do?

Nope, this is the syllabus that i've been using for my students for the past 3 years. They've not changed it since then and i'm sure, it'll still be the same this year

If we are to follow the syllabus, the picture below shows the first four topics in chemistry.....

Destilo:
what volume of Carbon(II)Oxide is produced by reacting excess carbon with 10dm cube of oxygen?

2C + O₂ --> 2CO
From the equation above, we can see that 2 moles of CO are produced when 1mole of Oxygen reacts with excess carbon and according to gay lusaac's law of combining volumes, the ratio of the volumes will be constant i.e.O₂ : CO = 1 : 2 ;
Therefore, 10dm^3 of Oxygen will produce 2(10) = 20dm³

It should also be noted that
1000 kg/m³ = 1000 g/l = 1 g/cm³ you really need to be careful of this when converting

It should be noted that ice has a lower density than either water (freshwater) or seawater (saltwater), so it will float in them. Seawater, however, has a higher density than freshwater, which means that the seawater will sink when it comes in contact with freshwater. This behavior causes many significant ocean currents and the concern of glacier melting is that it will alter the flow of seawater -- all from the basic functioning of density.

Density of an object was first discovered by a Greek scientist called Archimedes. It is simply a measurement of how compact the matter that made up the mass of an object is. If the matter is tightly held together the density of the object will be higher while the reverse is the case.

Density can also be defined as the mass per unit volume of a substance.

The density of an object can be obtained by using the mass of the object divided by the volume of the object.

Density = mass / volume (kg/m3)

The SI unit of density measurement is kg per cubic meter (kg/m3). Density can be found in use in many different areas in physics.

The symbol for density is the Greek letter rho, :

From the above explanations, it is obvious that between solids, liquids and gases, solids are the most dense(have the highest density), followed by liquids and then gases.... more updates to follow

Benjaminbest:
before solving such question u must understand d image given and d lens use.....lets not make dis an issue iam waiting for ur explanation on density

I'm not making it an issue here, you said I'm wrong and made it look as if I didn't know what I was doing at all and that's why I'm asking you to point out my mistake because I was and am SURE that my solution is very correct. Anyway, that's bygone, I'll give my contribution on density when I'm through with these classes ahead of me to take.
#peace

bobolizim:
nop he isnt an illiterate even he is in unilag 200l...he is more dan briiliant gan...he is a genius...do u no command millitary school?but i asked to tell me if it wrong notbto abuse him love....ok?

lol

Benjaminbest:
guy u are good dat is d truth but u have to see boyond d question dat is given before solving it

You still haven't told me where I got it wrong o, you got 32cm like I did after modifying your post, does that mean also wrong? (The only mistake I can see in my solution is typographic "+" instead of "-" which didn't affect my actual computations)
BTW, compare the solution you gave to mine and tell me which is more confusing and which is more explanatory. And would you mind giving us a diagram to buttress your explanation? I think that will throw more light to this......

Benjaminbest:
no doubt d second question u got it ryt but d first is wrong

Since you think it's wrong, I'm very eager to see the right solution boss.

Destilo:
@Mathefaro...n other maths expert in d house...
Help me solve this:

1. The first term of an AP is 3 and the eleventh term is 18. Find the number of terms in the progression if the sum is 81.



thank u

a = 3, T₁₁ = 18; Sn = 81, n = ?
For an arithmetic progression, A.P, Tn = a + (n - 1)d
Hence,T₁₁ = a + 10d = 18
And since a = 3, 3 + 10d = 18
10d = 15
d = 3/2 = 1.5
Also, for an A.P, Sn = (n[2a + (n - 1)d])/2,
Hence Sn = (n[2a + (n - 1)d])/2 = 81
Recall that a = 3 and d = 1.5
Therefore Sn = (n[2*3 + (n - 1)1.5])/2 =81
Cross multiplying gives:
n(6 + 1.5n - 1.5) = 162
=> n(1.5n + 4.5) = 162
=> 1.5n² + 4.5n - 162 = 0
=> use any suitable method to solve the quadratic equation to get n as 9, the other value is negative(-12) and will be discarded since n cannot be negative

Benjaminbest:
try again

what does this mean, that I'm wrong? I'm anxiously waiting for your correction......Albeit the post have has been modified.

Benjaminbest:
#a lens of focal length 12cm form an upright image three times d size of a real object. D distance between d object and d image is.

f=12cm; v = 3u
Using the mirror formula, 1/f = 1/u + 1/v;
1/12 = 1/3u + 1/u
multiplying through by 12u (l.c.m.), we have
12u(1/12) = 12u(1/3u) + 12u(1/u)
u = 4 + 12
u = 16
Therefore v = 3*16 = 48
Therefore, the distance between the object and image = u + v = 16 + 48 = 64cm
(I forgot it's a real image so it's i nthe front of the mirror, which is the same side on which the object is)
v + u = 48 - 16= 32cm

#a load of 5N gives an extention of O.56cm in d wire which obeys hooke law. What is d extention cause by a load of 20N

According to Hooke's law, f = ke
F1 = 5N, e1 = 0.56cm, f2 = 20N, e2 = ?
F1/e1 = f2/e2
5/0.56 = 20/ e2
e2 = 4*0.56 = 2.24cm

Segipaul:
3. A 5kg mass on a horizontal platform accelerated at the rate of 0.1m/s^2 when a horizontal force of 10N is applied to it. Calculate the coefficient of friction between it and the platform (g=10m/s^2)

m = 5kg; a = 0.1m/s²; horizontal force = 10N
Frictional force, F = ?
Accelerating force f = ma
= 5*0.1 = 0.5N
Frictional force = Horizontal force - accelerating force
F = 10 - 0.5 = 9.5N
Reaction force, R = mg
=> 5*10 = 50N

Therefore, the coefficient of friction, U = F/R
=> 9.5/50
= 0.19
It has no unit

Segipaul:
1. How much work is needed to stop a 20g bullet moving with a speed of 150m/s

The work needed to stop the bullet = energy possessed by the moving bullet(kinetic energy)
M = 20/1000 = 1/50kg (converted the g to kg)
V = 150m/s
K.E = ½mv²
=> ½*1/50*150*150
= 225J

2. An object of mass 10kg is placed on an inclined plane at 30degree to the horizontal. Calculate the reaction between the two surfaces (g=10m/s^2)

m = 10kg; g = 10m/s², © = 30^o(let theta = ©);
Reaction force, R = mgCos©;
=> R = 10*10*Cos30
=> R = 100*0.866
=> R =86.6N

Battery low o!! I'll continue later

Destilo:
1. A car travelling at 50m/s from rest covers a distance of 10km in 40min. Calculate the acceleration.

the question is kinda wrong, I'm guessing probably with the time or with the initial velocity, because even without accelerating, if the car continue to move with speed, 50m/s, it'll exceed a distance of 10km in 40mins

Destilo:
Wao...u re gud
thank u

you're welcome

Destilo:
@chim and other physics expert in d house..
Help me in dis, I need to know if I got it right.thank u.

1. The average velocity of a car is 54km/h. what is the distance covered if the time taken is 10s?

First and foremost, convert the average velocity to m/s by multiplying by 5/18
==> v = 54 * 5/18 = 15m/s;
Then recall that distance = average velocity * time taken i.e. S = vt
S = ?; v = 15m/s; t = 10s
Therefore, S = 15 * 10 = 150m

2. A car starts from rest and travels at uniform acceleration until it attains a velocity of 30m/s after 6s. The distance covered is?

Since the car started from rest, initial velocity, u = 0, v = 30m/s; t = 6a; a = v/t = 30/6 = 5m/s²; S = ?
So with the available parameters, S, u, a and t, the appropriate equation to use is S = ut + (1/2)*at²;
Therefore, S = 0(6) + 0.5*5*36
S = 0+ 90
S = 90m

3. A man increased his speed by 5m/s after 30s, if his initial velocity was 20m/s. The average distance covered if his speed was at uniform acceleration would be?

V - U = 5m/s; t = 30s; U = 20m/s;
a = (V - U)/t = 5/30 = 1/6m/s²
S =ut + ½at²
S = 20(30) + ½*1/6*30*30
==> S =600 + 75
==> S = 675m

4. A ball is thrown vertically upwards from the ground with an initial velocity of 50m/s. What is the total time spent by the ball in the air (g=10m/s.sq)

thank you

u = 50m/s; v = 0; t = ?, g = 10m/s²
=> V = u - gt (minus because the body is going up against gravity)
=> 0 = 50 - 10t
=> 10t = 50
=> t = 5s

Good morning lovely people

Destilo:
thank u very much

you're welcome

thankyouJesus:
Jeez, thank you. I would have prefer to go to UI but their academic calender is a little bit slow (considering age thing *employment/marriage/etc), do you think you talk sense into me?

it is not too slow

Destilo:
pls kindly help me in this...@mathefaro n other maths expert in d house...

Express 110011.1001 base 2 to
1. Octal
2. Hexadecimal
3. Base 4


I got the whole number side...but find it hard to get the fractional parts...after converting it to base 10, can't convert d fractional parts to the bases above..

Thank you very much

To convert the binary number(110011.1001) to hex is easy just break it into groups of four numbers, 0011 0011 . 1001 (note that I added extra two 0s to the left to make it balanced) now with it broken into segments of four use the conversion for binary, so using the table below you get your Hex number 33.9

Hex Binary
0 = 0000
1 = 0001
2 = 0010
3 = 0011
4 = 0100
5 = 0101
6 = 0110
7 = 0111
8 = 1000
9 = 1001
A = 1010
B = 1011
C = 1100
D = 1101
E = 1110
F = 1111

Now for octal,all you do is break it down into groups of three, your number(110011.1001) broken down would look like this 110 011 . 100 100 (note that I added extra two 0s to the right side to make it balance) then all you do is convert to octal using the table below. which you get 63.44 in octal.

Octal Binary
0 000
1 001
2 010
3 011
4 100
5 101
6 110
7 111

hope that helps.

Destilo:
pls kindly help me in this...@mathefaro n other maths expert in d house...

Express 110011.1001 base 2 to
1. Octal
2. Hexadecimal
3. Base 4


I got the whole number side...but find it hard to get the fractional parts...after converting it to base 10, can't convert d fractional parts to the bases above..

Thank you very much

I'll answer this with a long illustration
E.g convert 7562.45 which is a decimal number to a number in base 8(octal)

To convert integer decimals to octal, divide the original number by the largest possible power of 8 and successively divide the remainders by successively smaller powers of 8 until the power is 1.

Thus we get the following with the Integer 7562

7562 / 8^4 = 1 :::: It equals 1 because 8^4 can only go into 7562 once

Therefore, 7562 - ((8^4) x 1))
=> 7562 - 4096 = 3466

Now 3466 / 8 ^ 3 = 6 :::: because 8^3 goes into 3466 six times

Therefore, 3466 - ((8^3) x 6)
=> 3466 - 3072 = 394

Now 394 / 8^2 = 6 :::: because 8^2 goes into 394 six times

Therefore, 394 / ((8^2) x 6)
=> 394 - 384 = 10

Now 10 / 8^1 = 1 :::: because 8^1 goes into 10 once only

Therefore, 10 / ((8^1) x 1)
=> 10 - 8 = 2

Now 2 / 8^0 = 2 :::: because 8^0 goes into 2 twice

Therefore, 2 / ((8^0) x 2)
=> 2-2 = 0

So if we start from the beginning:

The first attempt to divide highest power into 7562 yielded us a 1.
Next it yielded a 6
Then another 6
Then a 1
Finally a 2

Thus the octal for 7562 = 16612


=====================
Now for the Decimal Places
=====================

To convert a decimal fraction to octal, multiply by 8; the integer part of the result is the first digit of the octal fraction. Repeat the process with the fractional part of the result, until it is null or within acceptable error bounds.

0.45 x 8 = 3 + 0.6 :::: so the first yield is a 3

We take the remaining decimal now,

0.6 x 8 = 4 + 0.8 :::: so the next yeild is a 4

We take the remaining decimal now,

0.8 x 8 = 6 + 0.4 :::: so the next yield is a 6

We take the remaining decimal now,

0.4 x 8 = 3 + 0.2 :::: so next yield is a 3

OK at this point if you continue you will notice a recurring theme. If we multiple 0.2 x 8 that will leave a decimal remainder 0.6, which multiplied by 8 will leave a decimal remainder of 0.8 etcetera.

There is no point continuing so the octal of 0.45 = 0.3463

Thus the octal of 7562.45 = 16612.3463



===========================
Let's do another decimal that ends
obviously to illustrate why you stop
when its obvious you have reached
limit of the decimal octal.
===========================

0.1640625

So, as before multiple by 8 to yield a answer and continue with remaining decimals till satisfied.

Thus,

0.1640625 x 8 = 1 + 0.3125 :::: first yield = 1

0.3125 x 8 = 2 + 0.5 :::: second yield = 2

0.5 x 8 = 4 + 0.0 :::: third yield = 4

Thus 0.1640625 = 0.124 octal

If only they were all that obvious eh

OK, I hope this helps you understand how to handle the Integer and Decimals when converting to a Octal number.

Hang in there, it gets easier the more you practice.

There's another simplified way of doing it in the computer science world, I'll post that also....

callmebeauty:
I hv bin given admission in the skul I chose as my second choice wic is a state skul,I'm still pending d payment of my acceptance fee just because I'm waiting for UI pass list.pals,wen r they going to release d list?

please which school is that and what course did you apply for?

Benjaminbest:
guys before i go update....make una tell me d differences between moving coil galvanometer and hot iron ammeter. Guys before u una resonate with my question make una wave for mind so dat u guys will b frequent with maximum velocity. Jst before i accelerate to d next level make my weight no become scalar

moving coil galvanometer responds only to direct currents(DC), it is used for detecting very small amounts of current the current to be measured is sent through a coil suspended or pivoted in a fixed magnetic field, and the current is determined by measuring the resulting motion of the coil.

while hot wire ammeter is an ammeter which measures alternating or direct current by sending it through a fine wire, causing the wire to heat and to expand or sag, deflecting a pointer. Also known as thermal ammeter

Destilo:
thank u @mathefaro
ok...but I found d question via physics textbook

like I said in the other thread, bearing is bearing irrespective of where you've seen it

Destilo:
Its physics question not maths...
ok...its still complicated...
what about the 5km?

my sister, bearing is bearing, whether physics or math. It's obvious that the 5km there is not needed, it's just a distraction

maxibrainz:
1. Merriam Webster dictionary the best offline dictionary for android, it is 100mb in size
2. world fact book: gives you details about the economy, government, people, culture, energy and society of any country in the world
3. English synonym and antonym
4. The Nigerian constitution

I guess you've not tried OALD, mind you, I also have Merriam Webster.