Why do you think there is a need for three layers in a film

Answer:

3

Explanation:

It is based on empirical evidence

The characteristic of science is that it is based on empirical evidences comprising of a hypothesis.

Hypothesis can be defined as an assumption which is made for the sake of argument . It is an interpretation of a practical condition for which action needs to be taken.It is defined as a tentative assumption which is made to test logical consequences.It is an antecedent clause of a statement which is conditional.

It is constructed before research. There are six types of hypothesis 1)simple hypothesis 2) complex hypothesis 3) directional hypothesis 4)non-directional hypothesis 5) null hypothesis 6)casual hypothesis

The hypothesis should be clear and precise, it must be specific and way of explanation of hypothesis should be simple.

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Answer:

The energy transported by a wave is directly proportional to the square of the amplitude. So whatever change occurs in the amplitude, the square of that effect impacts the energy. This means that a doubling of the amplitude results in a quadrupling of the energy.

It attempts to explain the idea that:C. energy is quantized

Answer:

See explanation

Explanation:

Before the advent of the wave-particle duality theory proposed by Louis de Broglie, there was a sharp distinction between mater and waves.

However, Louis de Broglie introduced the idea that mater could display wave-like properties.  Erwin Schrödinger developed this idea into what is now known as the wave mechanical model of the atom.

In this model, electrons are regarded as waves. We can only determine the probability of finding the electron within certain high probability regions within the atom called orbitals.

This idea has been the longest surviving atomic model and has greatly increased our understanding of atoms.

Answer:

B. 3+

Explanation:

When Fe²⁺ loses an electron, it becomes an Fe³⁺ ion.

   The loss of an electron in an atom makes the atom becomes positively charged. Further losing electrons makes the atom more positive.

 For the given ion;

 Fe²⁺   if it loses an electron more, it becomes Fe³⁺.

The expression is given as:

         Fe²⁺    →    Fe³⁺  +  e⁻

Answer:

B. Halogen

Explanation:

Halogens are the family of chemical elements found in the group VIIA of the periodic table which means they possess seven (7) outer electrons. Some examples of halogens are Fluorine (F), Iodine (I), Bromine (Br), and Chlorine (Cl).

A halogen, or an element located in group 7A, will form a salt when reacted with a metal atom.

For example, when Chlorine reacts with Sodium it would form a salt known as Sodium Chloride.

Na + Cl ----> NaCl

Answer:

B. A carbon monoxide molecule(CO)

Explanation:

CO is polar because oxygen is more electronegative than carbon, so it gives oxygen a partial negative charge and carbon and partial positive charge. This causes a net dipole moment. CO2 is linear with no net dipole moment because each C-O bond is equal and opposite to each other, so they equal 0, which makes them non polar.

Answer:

0.01M = [H⁺]; 1x10⁻¹²M = [OH⁻]; Ratio is: 1x10¹⁰

Explanation:

pH is defined as -log [H⁺]

For a pH of 2 we can solve [H⁺] as follows:

pH = -log [H⁺]

2 = -log [H⁺]

10^-2 = [H⁺]

Using Keq of water:

Keq = 1x10⁻¹⁴ = [H⁺] [OH⁻]

1x10⁻¹⁴ / 0.01M = [OH⁻]

The ratio is:

[H⁺] / [OH⁻] = 0.01 / 1x10⁻¹² =

Answer:

1. 0.01 mol/L

2. 0.000000000001 mol/L

3. 10000000000:1

Explanation:

Answer:

B. bedrock structure.

Explanation:

A landform refers to a geomorphic or natural feature of the Earth's surface, which typically makes its terrain. Some examples of landforms on planet earth are mountain, plains, valley, hills and plateau.

Basically, the tectonic plates such as the oceanic and continental lithosphere interact in three (3) ways and these are; divergent, transform and convergent boundaries.

A convergent plate boundary can be defined as a boundary where two (2) plates move towards each other, usually, resulting in subduction or collision. This action often causes mountain range such as the Himalayas to form by the collision between the plate carrying Eurasia and that of India; as a result of subduction which causes a plate to be forced underneath the mantle, deep ocean trenches are formed such as the Mariana trench.

The Catskills are commonly called mountains but are actually part of the Allegheny Plateau also referred to as Appalachian Plateau. The Catskills are classified as a plateau because of their bedrock structure which is caused by a valley, continental glaciers, and erosion from various watercourse.

Additionally, the Catskills is a mountain which got its name from early Dutch settlers in the United States of America.

Answer:

yes

explanation:

yes because when the velocity is low, all the energy is low and nothing can't do nothing without energy

Answer:

a.the same as

Explanation:

The temperature of each 400mL bucket is about the same as the temperature of the original bucket of paint.

This is because the temperature of the paint inside the bucket is not dependent on the amount of paint present.

Answer:

Weaker

Explanation:

Since the charges on nucleus and electron are opposite in nature, an attractive force exists between them. It is true in generally, that when objects are made to move closer together in the direction of an attractive force, potential energy decreases (and increases whenever attracting objects are force to move apart).

Here, we are required to determine if the attraction or repulsion grow weaker or stronger.

First, we must establish scenarios when there can be attraction and ones where there can be repulsion.

By the law guiding electric charges; In electrical interactions:

Like poles repel while Unlike poles attract.

Ultimately, when an electron gets closer to the nucleus, the attraction force will grow stronger due to the reduced distance between the electron and the nucleus.

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Boyle's law states that the pressure of the given quantity inversely varies with its volume at a constant temperature.

Answer:

2.8g/cm³

Explanation:

Given parameters:

Mass of cube = 42g

Volume of cube  = 15cm³

Unknown:

Density of the cube  = ?

Solution:

Density is defined as the mass per unit volume of a substance. It is mathematically expressed as:

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

So;

 Density  = [tex]\frac{42}{15}[/tex]   = 2.8g/cm³

Answer: It's A

Explanation:

Answer:

A

Explanation:

Answer:

Polar molecules occur when there is an electronegativity difference between the bonded atoms. Nonpolar molecules occur when electrons are shared equal between atoms of a diatomic molecule or when polar bonds in a larger molecule cancel each other out.

Explanation:

Polar molecules occur when there is an electronegativity difference between the bonded atoms. Nonpolar molecules occur when electrons are shared equal between atoms of a diatomic molecule or when polar bonds in a larger molecule cancel each other out.

Answer:

distance velocity displacement, all three

Explanation:

Answer:

As Naphthalene undergoes sublimation, we use sublimation process. On condensing naphthalene can be separated.

Answer:

278.1g/mol

Explanation:

To find the molar mass of the given compound, we must know the atomic mass of the elements within the compound.

Atomic mass of Mg = 24.3g/mol

Atomic mass of I  = 126.9g/mol

So;

  Molar mass  = 24.3 + 2(126.9) = 278.1g/mol

The molar mass of the compound is  278.1g/mol

Answer:

C. Equations that separate the oxidation and reduction parts of the reaction.

Explanation:

Redox half-reactions are actually used when balancing redox reactions. It gives the oxidation or reduction reaction components/parts of a redox reaction.  The change in oxidation and reduction states in the substances that are involved in a redox reaction is used to obtain a redox half-reaction.

This redox half-reaction can also be used to explain what takes place in an electrochemical cell; how the anode is undergoing oxidation and how the cathode is undergoing reduction.

Below is an example of a redox half-reaction:

2 Fe³⁺(aq) + 6e⁻ → 2 Fe(s) (Reduction)

3 Mg(s) → 3 Mg²⁺(aq) + 6e⁻ (Oxidation)

Explanation:

Atomic Number :

It only explain number of protons and electrons in nuclous

Atomic Mass :

Atomic mass tell how much neutrons are present in atom.

Answer:

[tex]\underline{ \boxed{atomic \: number = atomic \: mass - neutron \: number}} \\ \underline{ \boxed{atomic \: mass = proton \: number + neutron \: number}} \\ \underline{ \boxed{neutron \: number = atomic \: mass - proton \: number}}[/tex]

Explanation:

[tex] \underline{ \boxed{1}} \\ ATOMIC \: NUMBER = (atomic \: mass \: number\: - neutron \: number \: )\\ (which \: is \: same \: as ) = \: \underline{ \boxed{proton \: number}}\\ \\ \underline{ \boxed{2}} \\ ATOMIC \: MASS = (proton \: number \: + neutron \:number) \\ (is \: same \: as ) = \: \underline{ \boxed{sum \: of \:atomic \: nuclear \: content}} \\ \\ \underline{ \boxed{3}} \\ neutrons = (atomic \: mass \: number - proton \: number) \\ [/tex]

Answer:

by focal length of the eyepiece.

Explanation:

hope it helps!!plz mark as brainleist.

Answer:

Water can be used as the thermometric liquid. It expands and contracts with temperature so it can be used. It's just not a very good choice because: It's thermal expansion is not very large compared to other liquids like mercury.

Explanation:

Hope this help

Answer:

protozoan

Explanation:

An animal - like unicellular protist is called a protozoan. Such organisms shows similarities with animals.

Answer shallow ocean

Explanation:

i think

Answer:

See explanation

Explanation:

A pure liquid has a sharp boiling point. Now we know that the boiling point of water is 100°C.

If Laura begins to heat each liquid with a thermometer inserted into each liquid, the liquid that boils at exactly 100°C is pure water while the rest are solutions.

0.50 mol SiO₂

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Atomic Structure

Step 1: Define

30 g SiO₂ (sand)

Step 2: Identify Conversions

Molar Mass of Si - 28.09 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of SiO₂ - 28.09 + 2(16.00) = 60.09 g/mol

Step 3: Convert

Step 4: Check

Follow sig figs and round. We are given 2 sig figs.

0.499251 mol SiO₂ ≈ 0.50 mol SiO₂

Answer:

[tex]\boxed {\boxed {\sf About \ 0.5 \ moles \ of \ SiO_2}}[/tex]

Explanation:

To convert from grams to moles, we must use the molar mass.

1. Molar Mass

Use the Periodic Table to find the masses of the individual elements (silicon and oxygen) in sand.

Examine the formula for sand: SiO₂. There is a subscript of 2 after oxygen, so there must be 2 oxygen atoms. Multiply oxygen's mass by 2 and add silicon's mass to find the molar mass of sand.

2. Calculate Moles

Use the molar mass as ratio.

[tex]\frac{60.083 \ g \ SiO_2}{1 \ mol \ SiO_2}[/tex]

Multiply by the given number of grams (30)

[tex]30 \ g \ SiO_2 * \frac{60.083 \ g \ SiO_2}{1 \ mol \ SiO_2}[/tex]

Flip the fraction so the grams of sand will cancel.

[tex]30 \ g \ SiO_2 *\frac{1 \ mol \ SiO_2}{60.083 \ g \ SiO_2}[/tex]

[tex]30 *\frac{1 \ mol \ SiO_2}{60.083 }[/tex]

[tex]\frac{30 \ mol \ SiO_2}{60.083 }[/tex]

[tex]0.499309289 \ mol \ SiO_2[/tex]

3. Round

The original measurement of grams has 1 signfiicant figure. We must round our answer to 1 sig fig.

For the answer we found, that is the tenth place. The 9 in the hundredth tells us to round the 4 to a 5.

[tex]\approx 0.5 \ mol \ SiO_2[/tex]

There are about 0.5 moles of SiO₂ in 30 grams.