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Answer:

When no coefficient is written in front of a formula it is assumed to be 1. 4. Numbers appearing in the formulas are known as subscripts. These can never be changed when balancing the equation or you will change the identity of the substance.

Explanation:

1. Reactants go on the left hand side and products go on the right hand side of a chemical equation. Be sure to write the correct formulas for the reactants and products.

· Remember atoms are conserved in a chemical reaction. ie they are neither created or destroyed. So all the atoms in the reactants must end up somewhere among the products.

2. Count the number of atoms of each element, compound or ion in the reactants and products. If they are not equal proceed further.

3. Balance the atoms one at a time by placing coefficients in front of the formula so that the numbers of atoms of each element are equal on both sides of the equation. Remember atoms may exist in an element, compound or ion.

· It is usually easier to start with the atoms that occur in only one substance on each side of the equation.

· Balance the atoms that occur in compounds before attempting to balance atoms that occur in elemental form. e.g. H2, O2 or Cl2

· To make it easier if a polyatomic ion appears unchanged on both sides of the equation treat it as a whole unit.

· When no coefficient is written in front of a formula it is assumed to be 1.

4. Numbers appearing in the formulas are known as subscripts. These can never be changed when balancing the equation or you will change the identity of the substance.

· Remember with subscripts, any number to the right of parentheses multiplies each subscript within the parentheses.

eg Fe2(SO4)3 contains 2 Fe atoms, 3 S atoms and 12 O atoms.

5. Finally make sure that all the coefficients are in the smallest possible whole number ratio.

The number which we will never use as a coefficient in any chemical reactions are decimals and fractions.

Coefficients are the numbers which are written before any chemical entity of any chemical reaction.

Coefficients of any reaction will not be:

Coefficients are generally use for balancing the chemical reactions.

So, we will not use decimals and fractions as a coefficient.

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Answer:

X represents barium - 141 nucleus.

Written as: (141, 56) Ba

Explanation:

In nuclear fission reaction, due to the fact that the process produces more neutrons, a nuclear chain reaction can possibly occurr. Now, a chain reaction is a one whereby the material that begins the reaction will also be one of the products and it can start another reaction.

Now, for the nuclear chain reaction for the fission of uranium-235, its nucleus absorbs a neutron after which it splits into a krypton - 92 nucleus and a barium - 141 nucleus. Thereafter it releases three more neutrons.

Thus, X is the image represents barium - 141 nucleus.

(141,56) Ba

Answer:

The Force

Explanation:

Answer:

All chemical reactions occur at different rates

Answer:

1. The volume of displaced fluid is equivalent to the volume of an object fully immersed in a fluid or to that fraction of the volume below the surface of an object partially submerged in a liquid. The weight of the displaced portion of the fluid is equivalent to the magnitude of the buoyant force.

Why would you use this method?

So it can be used to accurately measure the volume of the human body and other oddly shaped objects by measuring the volume of fluid displaced when the object is submerged.

2. Density, mass of a unit volume of a material substance. The formula for density is d = M/V, where d is density, M is mass, and V is volume. Density is commonly expressed in units of grams per cubic centimetre.

What happens to things that are denser?

Students should realize that if an object weighs more than an equal volume of water, it is more dense and will sink, and if it weighs less than an equal volume of water, it is less dense and will float.

What happens if they are less dense?

The density of an object determines whether it will float or sink in another substance. An object will float if it is less dense than the liquid it is placed in. An object will sink if it is more dense than the liquid it is placed in.

Answer: Selenium is a member of the sulfur family with elements including tellurium and polonium. This family has six electrons in the outermost shell. Selenium specifically has an electron configuration of 2-8-18-6. The six electrons in the outermost shell allow selenium to have a variety of valence numbers.

Explanation:

Answer:

I think its b

Explanation:

Sorry if wrong! Hope this helps tho! maybe mark me brainliest if I am?

Answer:

B

Explanation:

Answer:

Explanation:

7.706 g of CO₂ will contain 12 x 7.706 / 44 g of C

= 2.1 g of C .

This will be contained in 3.256 g of isopentyl acetate

3.156 g of H₂O will contain 2 x 3.156 / 18 g of H

= .351 g of H

This will be contained in 3.256 g of isopentyl acetate

Rest will be oxygen

amount of oxygen in 3.256 g of isopentyl acetate

= 3.256 - ( 2.1 + .351 )

= .805 g

ratio of C , H , O in isopentyl acetate

= 2.1 g : .351 g : .805 g

2.1 / 12 : .351 / 1 : 0.805 / 16 ratio of moles

= .175 : .351 : .05  ratio of moles

= 3.5 : 7.02: 1

= 7 : 14 : 2

empirical formula of  isopentyl acetate

= C₇ H₁₄ O₂ .

Answer:

ΔT = 0.843 °C

Explanation:

Given data:

Heat added = 0.484 J

Mass of water = 0.1372 g

Temperature increase = ΔT = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Specific heat capacity of water is 4.184 j/g.°C

Now we will put the values in formula.

0.484 j = 0.1372 g × 4.184 j/g.°C× ΔT

0.484 j = 0.574j/°C× ΔT

ΔT = 0.484 j / 0.574j/°C

ΔT = 0.843 °C

Answer:

N2.

Explanation:

Answer:

10000000

Explanation:

Use wave equation: c=frequency * wavelength

c=3.00*10^8 m/s

Thus,

[tex]\frac{3.00*10^{8} }{30}[/tex]=10000000

Explanation:

Lithium is an electropositive element that readily loses electrons.

Oxygen is electronegative and it will readily accept electrons.

 Due to this significant electronegativity differences between the two species they form electrovalent or ionic bonds between them.

  2atoms of Li lose two electrons:

      Li  →  Li²⁺ + e⁻

             Lithium isoelectronic with helium

 For oxygen;

      O + 2e⁻   →  O²⁻

                          Oxygen is isoelectronic with Neon

Two ions of the lithium combines with the oxygen to form the bond;

                   4Li + O₂  →  2Li₂O

The electrostatic attraction between the two ions forms the ionic bond

Answer:

You can get 7 answers wrong.

Explanation:

Let's calculate the average

[tex]\frac{15}{2} \\\\=7.5[/tex]

So if you correctly answer 8 -15  (7.5 is approximated to 8 )questions correctly you will pass.

So you can get 7 answers wrong.

Answer:

Explanation: It’s the correct answer on Edmentum.

Answer:

The one on the top,'' As the water cool, it is returned to the boiler where it is heated,''

Explanation:

Because supergiants are so massive, the core temperature gets much hotter than in giants, so supergiants can fuse elements heavier than hydrogen and helium. But to support their tremendous mass, supergiants burn up their fuel much more quickly.

Answer:

because the core tempature gets much hotter.

Explanation:

so supergiants can fuse elements heavier than hydrogen and helium. But to support their tremendous mass, supergiants burn up their fuel much more quickly.

Answer:

The weight of the subducted plate produces a force to continue moving the plate.

Explanation:

Answer:

wood

Explanation:

hope this helps! good luck on ur test :)

Answer:

Wood

Explanation:

Answer:

reacts in air to form a green layer

Explanation:

Properties of substances can be physical or chemical. A physical property is that which does not affect the chemical composition of the substance(s) involved e.g melting point, boiling point, color, state of matter as depicted for copper (Cu) in this question.

On the other hand, chemical property of a substance are those properties that alters or affects the chemical composition of the substance. In other words, they are features that can be observed after the substance has undergone a chemical reaction. In this question, COPPER REACTING IN AIR TO FORM A GREEN LAYER IS A TYPE OF CHEMICAL PROPERTY because a chemical reaction has occured with the evidence of the green layer formation.

Answer:

What mass of silver will raise the level of the water in the graduated cylinder 1.50 mL? (Ans) 28.95 g / 1.50 mL = 19.3 g/mL (The gold's density)

19.3 gm/ml³ is the density of gold  .

Density, mass of a unit volume of a material substance. Density of a substance tells how close the particles of a substance are packed.

The formula for density is D = M/V, where d is density, M is mass, and V is volume.

Density is commonly expressed in units of grams per cubic centimeter.

The SI unit of density is kilogram per cubic meter (kg/m3).

It is also represented  in the c g s unit of grams per cubic centimeter (g/cm3).

To calculate density of gold (here):

Given,

Mass of gold=28.95 gm

Volume of water=1.50 mL

Density=?

Density =Mass/Volume

Density=28.95/1.50

Density=19.3 gm/ml³

Hence, 19.3 gm/ml³ is the density of gold .

Learn more about density ,here:
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Answer:

An open circuit is one where the continuity has been broken by an interruption in the path for current to flow. A closed circuit is one that is complete, with good continuity throughout. A device designed to open or close a circuit under controlled conditions is called a switch.

Answer:

electronegativity

Explanation:

Answer:

THe tendoncy is electronegstivity

Explanation:

Im a big brain person

Answer:

B. frozen or mummified fossils

This is the correct answer :)

Answer:

B the answer

Explanation:

frozen or mummified fossils

Answer:

The mass number of the atom is equal to the sum of the number of protons and neutrons in the nucleus

Explanation:

Each proton and each neutron weigh one amu( atomic mass unit), adding together the neutrons and protons and multiplying by 1 amu you get the mass of an atom

Answer:

it is 52.7

Explanation:

so when it is 30 the degree is 5°

when it is 60, the degree is 10°

when it is 90, the degree is 15° and so on...

Answer:

T₂ = 695.33 K

Explanation:

Given data:

Initial volume = 150 mL

Initial temperature = 25°C (25+273 = 298 K)

Final temperature = ?

Final volume = 350 mL

Solution:

The given problem will be solve through the Charles Law.

According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.

Mathematical expression:

V₁/T₁ = V₂/T₂

V₁ = Initial volume

T₁ = Initial temperature

V₂ = Final volume  

T₂ = Final temperature

Now we will put the values in formula.

V₁/T₁ = V₂/T₂

T₂ = V₂T₁ /V₁

T₂ = 350 mL × 298 K / 150 mL

T₂ = 104300 mL.K / 150 mL

T₂ = 695.33 K

Answer:

moles H = 2 x 0.0649=0.130

ions = 0.130 x 6.02 x 10^23=7.81 x 10^22

Explanation:

Answer:

the formula for mass number is "mass number = protons + neutrons".