Help with homework explain GRADE12 1-3 please

Answer:

The answer is D) Magnesium

Explanation:

Because smog is a mixture

sea water is a mixture

air is an element

And salt solvent

It can only be D

Answer:

what do you need help with?

Explanation:

Answer:

Because they have variable oxidation states

Explanation:

Transition metals are designated with roman numerals because they have variable oxidation states.

They do not form a single ionic ion as seen by the main group elements.

Answer:

Density = 2.08695652174

Explanation:

Density = Mass ÷ Volume

Answer:

4.50 L gas of fluorine at STP contain 0.2 moles.

Explanation:

Given data:

Volume of gas = 4.50 L

Number of moles F₂ gas  = ?

Temperature of gas = standard =  273.15 K

Pressure of gas = standard = 1  atm

Explanation:

Formula:

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K  

T = temperature in kelvin

Now we will put the values in formula.

1 atm × 4.50 L = n × 0.0821 atm.L/ mol.K  × 273.15 K

4.50 atm.L  = n × 22.43 atm.L/ mol.

n = 4.50 atm.L   / 22.43 atm.L/ mol.

n = 0.2 mol

4.50 L gas of fluorine at STP contain 0.2 moles.

Answer:

Summary. To summarize, the periodic table is important because it is organized to provide a great deal of information about elements and how they relate to one another in one easy-to-use reference. The table can be used to predict the properties of elements, even those that have not yet been discovered.

Answer:

True

Explanation:

Answer:

with there wings

Explanation:

birds have wings that flap up and down when they fly and this process repeats over and over

1. Structure of an atom:-

The basic structure of an atom includes a tiny, relatively massive nucleus, containing at least one proton and usually one or more neutrons.Outside of the nucleus are energy levels (also called shells), which contain one or more electrons.

Properties of an atom:-

The neutrons have the greatest mass and have no charge. The protons have slightly less mass than the neutrons and are positively charged. The electrons have almost no mass and are negatively charged. The chemical properties of the atom are determined by the number of protons, in fact, by number and arrangement of electrons.

2. Elements and their chemical symbols :-

1) Sodium - Na

2) Carbon - C

3) Magnesium - Mg

4) Aluminium - Al

5) Silicon - Si

6) Chlorine - Cl

7) Potassium - K

8) Calcium - Ca

9) Copper - Cu

10) Iron - Fe

3. ionic bond

Covalent bond

Metallic bond

4. pH scale used to specify the acidity or basicity of an aqueous solution. Acidic solutions are measured to have lower pH values than basic or alkaline solutions

5. There are four natural states of matter: Solids, liquids, gases and plasma.

6. Law of conservation of mass :

The 'law of conservation of mass' says that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. The mass of the products in a chemical reaction must equal the mass of the reactants.

Law of conservation of energy :-

According to the law of conservation of energy, energy can only be transformed from one form to another. It can neither be created nor destroyed. The total energy before and after the transformation always remains constant.

Answer:

C. Biotechnology

Explanation:

In its broadest definition, biotechnology is the application of biological techniques and engineered organisms to make products or modify plants and animals to carry desired traits. This definition also extends to the use of various human cells and other body parts to produce desirable products.

Answer:

Explanation:

Forms of the same atom that differ only in their number of neutrons are called isotopes. Together, the number of protons and the number of neutrons determine an element's mass number: mass number = protons + neutrons. ... A property closely related to an atom's mass number is its atomic mass.

Answer:

Net force= 0N or 0units

Object is balanced

Explanation:

Net force refers to all the sum total of all forces acting upon an object. In this case, a boy and a girl are pulling a heavy crate at the same time with 7 units of force each.

- This means that the force exerted on the crate by the boy is F1 = 7units

- The force exerted on the crate by the girl is F2 = -7units

Hence, the Fnet = F1 + F2

Fnet = 7 + (-7)

Fnet = 0 units

An object which possess a net force is said to be unbalanced, while an object with no net force i.e 0 units or N. Hence, the heavy crate in this case being pulled by a net force of 0units is BALANCED.

The force applied on the object is a balanced force since the object is at equilibrium.

The given parameters;

force applied by the boy, F₁ = 7 N

force applied by the girl, F₂ = 7 N

The net force on the object is the resultant of the two equal both opposite directed force.

Let the boy's direction be positive

Let the girl's direction be negative

The resultant of the two forces is calculated as;

[tex]\Sigma F_x = F_1 + F_2\\\\\Sigma F_x = (7 \ N) + (-7 \ N)\\\\\Sigma F_x = 0[/tex]

Thus, the force applied on the object is a balanced force since the object is at equilibrium.

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Answer:

left to right

The periods go on a periodic table, left to right. The periodic table is the systematic arrangement of elements in row and column.

The chemical elements are arranged in rows and columns in the periodic table, sometimes referred to as the periodic table of the elements. It is often used in physics, chemistry, and other disciplines, and is frequently regarded as a symbol of chemistry.

Because of the orderly arrangement of the elements, it is known as the periodic table. Periods refers to the horizontal rows, and Groups to the vertical columns.

The most significant role of hydrogen in the human body is to maintain your level of hydration, making it the most significant element on the periodic table.

All known elements are grouped together in the periodic table of elements into groups with related characteristics. It becomes a crucial tool for chemists, nanotechnologies, and other scientists as a result. You can forecast how chemicals will behave if you learn to utilize and comprehend the periodic table.

Thus, The periods go on a periodic table, left to right.

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Answer:

A

Explanation:

With the given choices, A would be correct for this question.  But, both liquids and gases have particles that are far apart so that they can fill their containers.

Answer:

120 degrees

Explanation:

The molecule has trigonal bipyramidal geometry.  The angle between B molecules is 120 degrees.  The angle between A and B molecules is 90 degrees.

The bond angle of B-C-B is equal to 120° as the given geometry of the molecule is trigonal bipyramidal.

The trigonal bipyramid formation in chemistry is a molecular geometry in which one atom is at the center and 5 more atoms are at the corners molecular structure.

The bond angles of this geometry surrounding the central atom are not identical because there is no geometrical arrangement with five terminal atoms in equivalent positions. For example, this molecular geometry is PF₅, PCl₅ in the gas phase.

In PCl₅, the P atom shares a plane with three Cl atoms at 120° angles to each other in equatorial positions, and two more Cl atoms above and below the plane or at axial positions.  An axial atom has three neighboring equatorial atoms at a 90° bond angle.

In the given figure, the B-C-B is present at the equatorial plane of the molecule. The angle between the bonds at the equatorial plane is 120°. Therefore, the angle of B-C-B is equal to 120°.

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H2O is covalent so A is false.

Water is in clouds so B is false.

Water is polar so C is false.

D is correct H2O has an imbalance of e- so it is polar. [tex]+H-O(-)-H+[/tex]

An unusual property of water is a polar molecule. Therefore, option D is correct.

When two atoms form a covalent bond but do not share their electrons equally, polar molecules are created. A dipole is created when a portion of the molecule has a slight positive charge and a slight negative charge.

Because the electrons of the hydrogen atoms are "drawn" toward the electrons of the oxygen atom, water (H2O) is a polar molecule. As a result, the hydrogen atoms have a positive charge, whereas the opposite end of the molecule has a negative charge.

Polarity is one of the special characteristics of water because it is composed of polar molecules. Each water molecule has one oxygen atom and two hydrogen atoms (H2O). Polar covalent bonds are created by these compounds. The atoms of hydrogen are positively charged.

Thus, option D is correct.

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Answer: The rows of the periodic table represent the highest energy level of that element.

The columns represent how many valence electrons that element has.

Groups are the same thing as columns, they represent how many valence electrons am element has.

The blocks of the periodic table represent what sublevel(s) the valence electrons fill.

Explanation: Yes

Answer:

I can help!

Explanation:

Blocks

Atomic symbol is the one- or two-letter symbol for each element.

Atomic number is the number of protons in the nucleus, which determines the order of elements on the periodic table. This is also the total number of electrons in neutral atoms of the element.

Atomic mass is the mass in grams of 1 mole of atoms. Note that 1 mole contains 6.022·1023 atoms.

Groups

The first two groups of the periodic table(Alkali metals and Alkali Earth metals) are the s-block. Note that helium, in the last column of the table, is also part of the s-block. The outermost electrons of these elements are in s orbitals.

The transition metals make up the d-block, with electrons filling d orbitals. The lanthanides and actinides make up the f-block, with electrons filling f orbitals.

Groups 13 through 18,(post transition metals, metalloids, Reactive nonmetals, and Noble gases-)except for helium, make up the p-block. The outermost electrons of these elements are in p orbitals.

Sections

Metals are more likely to lose valence electrons

nonmetals are more likely to accept electrons.

Metalloids may act like metals or nonmetals, either losing or gaining valence electrons depending on the situation.

Transition metals(groups 3-12) behave somewhat differently because they can lose electrons from their outermost s or d orbitals.

Noble gases are the elements in group 18 that don’t tend to react with other elements. Noble gases have completely filled outer electron shells, as you can see because they’re at the end of each period. The electrons in these elements are stable, making the elements unreactive.

Periods and Groups

Groups of elements have similar properties in terms of how they react with other elements.

All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor.

Hope this helps!!

Answer:

A. An atom

Explanation:

A large scale model is one that is bigger than the object itself. These are needed to visualise structures and behaviours that we cannot normally see. A large scale model is needed for small objects, such as an atom. Larger objects do not need even bigger models

Answer:

Melting: one substance is involved and the liquid and solid are the same material.

To melt something heat is essential.

Dissolving: involves two materials;the resulting solution is a mixture of two substances.

The dissolved substance is still present in the solution even though it cannot be seen.

Explanation:

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Answer:

It's actually C

Explanation:

The Ice's mass was never destroyed, just converted therefore it would be C, which states the mass never disappeared, just changed to water.

Answer:

(Ge)

Explanation:

I'm just taking a wild guess really!

The easiest easy to find about metal is through the periodic table. Most of the ele,mtns are metals and the only exception is hydrogen which is nonmetal as it's in its gaseous state.  

Learn more about the tests you could perform to determine if a substance was a metal or nonmetal.

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Answer:

B

Explanation:

PE=m*delta(h)*g

So 0.75*1.5*9.8 equals PE

=11.025 so round up

Answer:

Some abiotic factors of the taiga are temperature, precipitation, soil, and sunlight.

Explanation:

emperature affects the taiga because the winter temperature range is -65*F to 30*F (-54*C to -1*C), while the temperature range in the summer is 20*F to 70*F (-7*C to 21*C)

Precipitation affects the taiga because there's some precipitation that falls [30-85 cm. (12-33 in.)].

Soil affects the taiga because there's some acidic and low-in-nutrients soil, and some fertile soil.

Sunlight affects the taiga because there are small amounts of it that reach the ground.

The taiga biome's abiotic components include temperature, sunshine, soil, air, water, etc. Cold arctic air predominates in the taiga environment. The taiga receives more light in the summer, which causes the days to be hotter.

Abiotic elements, also known as abiotic factors, are non-living chemical and physical elements of the environment that have an impact on the health of living things and the operation of ecosystems. Biology as a whole is supported by abiotic causes and the phenomena that go along with them.

Biotic and abiotic components, such as rainfall, in that order. The taiga is the biggest biome on Earth's surface and features a diversity of migratory and resident creatures. It also has long, cold, and dry winters and short, warm, and moist summers.

The Taiga biome is restricted by four primary criteria. Fire, temperature, the quantity of nutrients in the soil, and sunshine are the four limiting elements. Because certain plants, like the Jack Pine, recover after fire, it is a limiting element in the Taiga biome.

Thus, The taiga biome's abiotic components include temperature, sunshine, soil, air, water, etc.

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