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Answer:

Explanation:

percentage error = error  x 100 / correct value

= (2.73 - 2.70) x100 / 2.70

= 1.11 %

The element is Aluminium whose density is 2.702 grams / cc

Boiling point of Aluminium = 2519⁰C .

Answer:

A. element

Explanation:

Answer: Element

Explanation: A substance that is composed of only one type of atom is called an element. At this point, what should amaze you is that all forms of matter in our universe are made with only 118 different building blocks.

Answer:

Explanation:

Ammonia consist of nitrogen and hydrogen.

Chemical equation:

N₂ + H₂    →   NH₃

Balance chemical  equation:

N₂ + 3H₂    →   2NH₃

We can see that nitrogen and hydrogen react with each other and from ammonia.

Nitrogen is present in group 5A.  The atomic number of nitrogen is 7.  Its atomic mass is 14 amu.  It has 5 valence electron.

Electronic configuration:

N₇ = 1s² 2s² 2p³

we can see there are five electron in outer most shell. Thus, nitrogen needs three more electrons to complete the octet.  When it combine with other atoms it gain three electron from them

While hydrogen is present in group 1A. It has one valence electron. In ammonia (NH₃) when nitrogen react with hydrogen it gain three electrons thus three atoms of hydrogen combine with one atom of ammonia because one hydrogen atom can share only one electron. Covalent bond is formed between nitrogen and hydrogen and new substance formed is called ammonia.

Answer:

D. Ruler

Explanation:

Use the formula to find the volume of a cuboid by measuring the length, width, and height and multiplying all of them by each other.

Answer:

hydrogen is a non-metal, and has one valence electron.

Explanation:

Hope this helps!!

Hydrogen shows properties of both metals and nonmetals. However, hydrogen is placed with the alkali metals since it contains one valence electrons.

Hydrogen is the first element in the periodic table. It has only one electron and it is the valence electron of hydrogen. Therefore, hydrogen is placed in the first group of periodic table.

Hydrogen needs one more electrons to become stable. The 17th group elements halogens also have a valency of  one. Hence, hydrogen shows some chemical similarities with halogens also.

Mostly hydrogen forms covalent bonds like non-metals and in rare cases, hydrogen forms ionic bonds by donating its electron. Therefore, hydrogen is mostly considered as a non-metal.

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Number of particles : 8.603 x 10²³

Standard conditions for temperature and pressure are used as a reference in certain calculations or conditions

Assumption⇒ Standard Conditions

Conditions at T 0 ° C and P 1 atm are stated by STP (Standard Temperature and Pressure). At STP, Vm is 22.4 liters/mol.

1 mol = 6.02 x 10²³ particles (atoms, ions, or molecules)

32.0 liters of Helium

[tex]\tt mol=32:22.4=1.429[/tex]

Number of particles :

[tex]\tt 1.429\times 6.02\times 10^{23}\\\\=8.603\times 10^{23}[/tex]

Answer: A

Explanation: Mortality means death. And it is a primary goal of Development Goals

Reducing child mortality, or rate of death, is one of the primary goals of the UN’s Millennium Development Goals and the correct option is option A.

Mortality is defined as the state of the individual being dead. The mortality rate is the death rate of a population which is calculated on the basis of the deaths in the particular region.

Mortality as one of the components of demography is measured as mortality rate.

Mortality meaning provides the basis for mortality rate and its estimation. Mortality is the possibility of and susceptibility to death, and hence, the rate of mortality or the death rate is the measurement of the number of deaths that occur in a particular population, scaled to the size of that population per unit of time.

Therefore, Reducing child mortality, or rate of death, is one of the primary goals of the UN’s Millennium Development Goals and the correct option is option A.

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Answer:

mole = no of atoms/ 6.02E23.... so therefore answer= 5.6E22/6.02E23= 0.093✨

Emission lines are seen as coloured lines on a black background. Absorption lines are seen as black lines on a coloured background. The presence of spectral lines is explained by quantum mechanics in terms of the energy levels of atoms, ions and molecules.

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Answer:

2.18 * 10^12 mg

Explanation:

1 nanogram [ng] = 10^6 milligram [mg]

2.18 * 10^6 ng/ 1 ng = X mg / 10^6 mg

X mg = 2.18 * 10^12 mg

Answer:

2.18 * 10^12 mg

Explanation

Answer:

Nuclear fission

Explanation:

This reaction is called a nuclear fission reaction. In this reaction, a radioactive decay process occurs in which a heavy nucleus spontaneously disintegrates into two lighter nuclei and several neutrons, with the release of a large amount of energy.

Answer:

By ensuring she is giving speed endurance training

Explanation:

Speed endurance training would be the most ideal in helping an athlete to maintain and even increase her competitive potential.

The speed endurance training would help the athlete maintain and attain a high speed for a longer duration of time.

This would make the athlete get used to running an improved time for much longer distances.

Answer:

Lithium oxide.......................

Explanation:

6. magnicium chloride

2.Barium chloride

3. calcium nitride

4. lithium oxide

5. Aluminium sulphide

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Answer:

There are 18 carbon atoms in a molecule of omega 3 fatty acid

Explanation:

Answer:

Au

Explanation:

trust me, the abbrevation for gold is Au. chemicaly, Medicaly, and in dentistry

Answer:

3.41 x 10^7

Explanation:

2H₂ + O₂ ⇒ 2H₂O

Conservation of mass states that

In a closed system, the masses before and after the reaction are the same

So it can be concluded

So let's see which of the several options , which one has the same number of atoms on both sides of the equation

2H₂ + O₂ ⇒ 2H₂O

H ⇒ left 4, right 4

O ⇒ left 2, right 2

so the equation is in balance and represents the Law of Conservation of

Mass

Answer:

Layer A is the youngest

Explanation:

It is at the top, it has all of the dinosaur bones which got buried after earth got hit with an asteroid and they went extinct. Layer D started it and all of these years dirt, soil, and fossils have been gathering making each layer before older and older.  

Answer:

personally I like the mortal kombat 11 better

Answer:

mortal combat 11.

Answer:

Lead

Explanation:

Lead (Pb) is the end product of every natural radioactive series.

9. (80-32)5/9

48×5/9

240/9

26.66°C

9. (90-32)5/9

58×5/9

32.22°C

10 (212-32)5/9

180×5/9

20×5

100°C

Answer:differentiate between two compounds i think!

Explanation: taking a test!

Answer:(1) differentiate between two compounds

Explanation:

A Chemical property tells us the  characteristics of a particular matter or substance after a  chemical change. This property helps us to differentiate a compound from another or differentiate   elements or substances. Examples of a Chemical property are  acidity, reactivity and heat, etc .

For example to differentiate between Water H2O and  Hydrogen peroxide, H202

Even though they are made up of  oxygen and hydrogen. Hydrogen peroxide  (H2O2), has  more(1) oxygen than water (H2O).

Using Acidity as a chemical property to differentiate these substances

Water, H20  is amphoteric in nature ie having both acidic and basic properties, while H202 is a weak acid.

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Answer:

5

Explanation:

mass/volume = density

30/5 = 5

Answer:

The 4th option

a possible explanation of or answer to a scientific question

Explanation:

Answer:

A hypothesis is a question about naturre and how it works

Answer:

the answer is 2 valence electrons

Answer: yes they are

Explanation:

because its so hot and the heat just stays at the bottom

Answer:

Tbh i rlly dont think that many will.  Most may succeed  in doing so. But i mean come on its 2020 anything can happen.

Explanation:

Answer:

yes 100% what reasons r there to not tho

Explanation:

Answer:c

Explanation:

Answer:

C is the answer

are in the outermost energy level