Niels Bohr’s model of the atom helped to explain

Answer:

istopes is a situation in which each of two or more forms of same element that contain equal number of proton....while ions of an atoms are with extra electrons or missing electrons so they tends to differ

Answer:

(The Formation Of Bands In A Crystal)

Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\[/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

[tex]n = \frac{13 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 21.594684...[/tex]

We have the final answer as

Hope this helps you

Answer:

1250kg

Explanation:

Given parameters:

Acceleration  = 1.2m/s²

Force  = 1500N

Unknown:

Mass on the vehicle  = ?

Solution:

According to newton's second law of motion:

  Force  = mass x acceleration

Since mass is the unknown, insert the parameters and solve;

       1500  = mass x 1.2

        mass = [tex]\frac{1500}{1.2}[/tex]   = 1250kg

Answer:

No numbers how are we supposed to know

Explanation:

Answer:

Both A and B

Explanation:

Answer: The answer is the last one: found in the nucleus of a cell

Explanation:

Each chromosome is made of protein and a single molecule of dna. As It is getting passed from the parents to the offspring the dna contains specific instructions that make each type of living thing unique.

Answer:

Based on the periodic law

Explanation:

All the elements on the periodic table were constructed based on the periodic law.

Henry Moseley in the 1900s re-stated the periodic law by changing the basis of the law from atomic weight to atomic number. The present periodic law is therefore "the properties of elements are a periodic function of their atomic number".

Before a titration, indicator is added to the analyte (which is in the flask, and usually the chemical of unknown concentration).  The titrant is then placed in a burette and slowly titrated into the analyte.  When the indicator changes color is when the endpoint of the titration has been reached.  This occurs (approximately) at the equivalence point.

The chemical equation is said to be balanced if the number of atoms in the reactants and products is the same

Equation balanced ⇒ total number of atoms in reactants(on the left)= total number of atoms in products(on the right)

H₂+O₂---> H₂O

Reactants : H₂, O₂

Products : H₂O

not balanced

H₂O₂ ---> H₂O+O₂

Reactants : H₂O₂

Products : H₂O, O₂

not balanced

Na+O₂ ---> Na₂O

Reactants : Na, O₂

Products :  Na₂O

not balanced

N₂+H₂ ---> NH₃

Reactants : N₂, H₂

Products :  NH₃

not balanced

P₄+O₂---> P₄O₁₀

Reactants : P₄, O₂

Products :  P₄O₁₀

not balanced

Fe+H₂O ----> Fe₃O₄ + H₂

Reactants : Fe, H₂O

Products :  Fe₃O₄

not balanced

Answer:

the amount of matter in the bowling ball remains the same

Explanation:

The reason why the mass of the bowling ball on earth and moon remains the same is that matter in the bowling ball remains the same.

Mass of any substance is the amount of matter it contains.

Answer:

mouse

Explanation:

Answer:

Oxygen

Explanation:

Oxygen is more reactive because it has small atomic size which has high tendency to attract more electrons.

Answer:

CsCl

Explanation:

The ionic species are:

            Cs⁺   and Cl⁻

The two ions will combine to form an ionic compound which results from the electrostatic attraction between oppositely charged ions.

Elements or ions exchange directly their combining powers or their simplest whole number ratio during the formation of chemical formulae of compounds

                                Cs⁺   and Cl⁻

Combining power      1             1  

Exchange of

valencies                     1             1

      Compound CsCl

Answer:

Mass = 114.26 g

Explanation:

Given data:

Number of gold atoms = 3.47×10²³ atoms

Mass in gram = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.  The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

3.47×10²³ atoms × 1 mol  /6.022 × 10²³ atoms

0.58 mol

Mass of gold:

Mass = number of moles × molar mass

Mass = 0.58 mol × 197 g/mol

Mass = 114.26 g

Answer:

The dependent variable is the number of clams developing from fertilized eggs.

The independent variable is the water temperature

The optimum temperature for clam development is 30 degrees centigrade.

Explanation:

The graph of the number of clams developing from fertilized eggs and water temperature is attached to this answer.

The independent variable is being manipulated in an experiment. As it changes, it produces a corresponding change in the dependent variable.

Here, the water temperature is the independent variable. As it changes, the number of clams developing from fertilized eggs (dependent variable) also changes alongside.

The optimum temperature is the temperature at which the greatest number of clams developing from fertilized eggs is produced. We can see from the graph that this temperature is 30 degrees centigrade.

There are 20.8 moles of propanol

The mole is the number of particles(molecules, atoms, ions) contained in a substance  

1 mol = 6.02.10²³ particles

Can be formulated

N=n x No

N = number of particles

n = mol

No = Avogadro's = 6.02.10²³

1.2 x 10⁵ molecules of propanol

[tex]\tt \dfrac{1.25\times 10^{25}}{6.02\times 10^{23}}=20.8~moles[/tex]

Answer:

30 molecules

Explanation:

easy

Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\ [/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

[tex]n = \frac{2.4 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{2.4}{6.02} \\ = 0.398671096....[/tex]

We have the final answer as

Hope this helps you

Answer:

A change in the shape of a substance

Explanation:

Because when ths shape of a sunstance changes , its physical appearance changes .A physical change is a change to the physical—as opposed to chemical—properties of a substance. They are usually reversible. The physical properties of a substance include such characteristics as shape (volume and size), color, texture, flexibility, density, and mass.

Answer:

ions

Explanation:

Individual atoms of the same element but having slightly different number of protons and electrons are called ions.

Ion is a charged particle.

When the number of protons > electrons the body is positively charged.

When the number of electrons > protons the body is negatively charged.

Charged particles are called ions.

Answer:

1. 0.25 moldm¯³.

2. 9.125 gdm¯³.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

2HCl + Na2CO3 → 2NaCl + H2O + CO2

From the balanced equation,

The mole ratio of the acid, HCl (nA) = 2

The mole ratio of the base, Na2CO3 (nB) = 1

1. Determination of the concentration of the acid, HCl in moldm¯³.

Volume of acid, HCl (Va) = 20 cm³

Volume of base, Na2CO3 (Va) = 25 cm³

Concentration of base, Na2CO3 (Cb) = 0.1 moldm¯³

The mole ratio of the acid, HCl (nA) = 2

The mole ratio of the base, Na2CO3 (nB) = 1

Concentration of acid, HCl (Ca) =?

Cava /CbVb = nA/nB

Ca × 20 / 0.1 × 25 = 2/1

Ca × 20 / 2.5 = 2

Cross multiply

Ca × 20 = 2.5 × 2

Ca × 20 = 5

Divide both side by 20

Ca = 5/20

Ca = 0.25 moldm¯³

Thus, the concentration of the acid, HCl in moldm¯³ is 0.25 moldm¯³

2. Determination of the concentration of the acid, HCl in gdm¯³

Concentration of the acid, HCl = 0.25 moldm¯³

Molar mass of HCl = 1 + 35.5 = 36.5 g/mol

Concentration of the acid, HCl in gdm¯³ =?

Conc. in moldm¯³ = Conc. in gdm¯³ /Molar mass

0.25 = Conc. in gdm¯³ /36.5

Cross multiply

Conc. in gdm¯³ = 0.25 × 36.5

Conc. in gdm¯³ = 9.125 gdm¯³.

Answer:correct

Explanation:

The large calorie, food calorie, or kilocalorie (Cal, calorie or kcal) is the amount of heat needed to cause the same increase in one kilogram of water. Thus, 1 kilocalorie (kcal) = 1000 calories (cal).

Answer:

Aluminium (A1) -Used in the production of duralumin alloy for use in the construction of aeroplane bodies. 3. Silicon (Si) -To make microchips 4. Sulphur (S) -To make matches, fireworks and for the manufacture of sulphuric acid 5.

Explanation:

Hope this helped!

Answer:

yes

Explanation:

we use different elements and compounds in our life ex salt and iron but most of the substances found in our environment are mixture btw scientists need to classified substances to work with our substances and to study pure substances hope it helps u

Hope this might help a little

Answer:

The answer is (c)

Explanation:

Answer:

C. The most common religion is Catholism.

Explanation:

I'm taking the quiz rn.

Answer:

Bellatrix.

Explanation:

Answer:

vega i believe just look at the number and see what kinda is less ykwim

Answer:

D

Explanation:

Answer:

The answers D.

Explanation:

Answer:

Its D

Explanation:

Just took the Test.