HELPPPPP

Identify whether each of the following changes is a physical change or a chemical change. Write “P” on the line for a physical change and a “C” for a chemical change.
22. Water boiling ______23. Iron rusting ______24. Butter melting _____25. Wood rotting ______
26.Alcohol evaporating _____27.Glass breaking ______28.Mowing the lawn ______29.Baking a cake ______

Answer: here u go

Explanation:

A. 3.7 x 10^4

B. 4.56 × 10^-8

C. 8.01 × 10^6

Work for A:

Step 1

To find a, take the number and move a decimal place to the right one position.

Original Number: 37,000

New Number: 3.7000

Step 2

Now, to find b, count how many places to the right of the decimal.

New Number: 3 . 7 0 0 0

Decimal Count:   1 2 3 4

There are 4 places to the right of the decimal place.

Step 3

Building upon what we know above, we can now reconstruct the number into scientific notation.

Remember, the notation is: a x 10b

a = 3.7 (Please notice any zeroes on the end have been removed)

b = 4

Now the whole thing:

3.7 x 104

Step 4

Check your work:

104 = 10,000 x 3.7 = 37,000

Work for B:

Step 1

To find a, take the number and move a decimal place to the right one position.

Original Number: 456

New Number: 0.0000000456

Step 2

Now, to find b, count how many places to the right of the decimal.

New Number: 0 . 0 0 0 0 0 0 0 4 5 6

Decimal Count:   1 2 3 4 5 6 7 8 9 10

There are 2 places to the right of the decimal place.

Step 3

Building upon what we know above, we can now reconstruct the number into scientific notation.

Remember, the notation is: a x 10b

a = 4.56

b = 2

Now the whole thing:

4.56 x 102

Step 4

Check your work:

102 = 100 x 4.56 = 456

Work for C:

Step 1

To find a, take the number and move a decimal place to the right one position.

Original Number: 8,010,000

New Number: 8.010000

Step 2

Now, to find b, count how many places to the right of the decimal.

New Number: 8 . 0 1 0 0 0 0

Decimal Count:   1 2 3 4 5 6

There are 6 places to the right of the decimal place.

Step 3

Building upon what we know above, we can now reconstruct the number into scientific notation.

Remember, the notation is: a x 10b

a = 8.01 (Please notice any zeroes on the end have been removed)

b = 6

Now the whole thing:

8.01 x 106

Step 4

Check your work:

106 = 1,000,000 x 8.01 = 8,010,000

Hope this helps!

Answer:

Group number, octet's rule, total number of bonds and fewest valence electrons.

Explanation:

Hello,

For the given statement is answer is bolded:

"When drawing the Lewis structure of a molecule, start by determining the total number of available valence based on each element's group number. Then, use the total number of electrons needed for each element to be stable, generally based on the octet's rule its charge, to determine the total number of bonds by finding the difference between the number of needed and available electrons divided by two.

Next, identify the central atom, which is the element with the fewest valence electrons other than hydrogen. Finally, arrange the number of bonds around the central atom to fulfill the stable number of electrons for each element".

For the first one, it is widely known that the group number provides the number of valence electrons as nitrogen is in group VA and it has five valence electrons, chlorine is in grou´p VIIA and it has seven valence electrons and so on.

For the second one, it is also known that the octet's rule limit the amount of bonds as it has been demonstrated that each compound can hold up to 8 electrons overall excluding some exceptions.

For the third one, based on the octet's rule, an element must have as much bonds as missing electrons to complete eight, for instance, carbon has four valence electrons, so it need four bonds (each one providing one valence electron) in order to attain the octet.

Finally, the central atom must have the fewest number of valence electrons as it shows the other bonds and elements attaining the octet. Usually, the central atom is not demanded to get 8 electrons, for instance in AlCl₃, which is:

[tex]\ \ \ \ \ Cl-Al-Cl\\.\ \ \ \ \ \ \ \ \ \ \ \ \ |\\.\ \ \ \ \ \ \ \ \ \ \ \ Cl[/tex]

Has aluminum as the central one due to the fact that it has three valence electrons whereas chlorine seven and it does not attain the octet.

Best regards.

Answer:

true

Explanation:

Condensation is the opposite of vaporization. True. When does condensation occurs, does a gas lose or gain thermal energy?

Answer:

True

Explanation:

Condensation is formed with moisture and cold air, so the removal of thermal energy, or heat, would create the perfect conditions :)

Explanation:

Oxygen will gain electrons to form ion (O²⁻).

Calcium loses electron to form ion (Ca²⁺)

Lithium loses electron to form ion (Li⁺)

Mercury loses electron to form ion (Hg²⁺)

Here it is stated in question that the element will gain electron it means electron bears negative charge.

Therefore,

Option A is correct ✔.

Answer:

Number of neutrons

Explanation:

All have one single proton.  Hydrogen has no neutrons.  Hydrogen 2 or deuterium has 1 neutron.  Hydrogen 3 or tritium has 2 neutrons.

Answer:

Use the data in the Successive Ionization Energies and Electron Affinity tables to determine the following. (Assume the values in the Successive Ionization Energies table are given to the ones place.)

(a)

the electron affinity of Ar2+

kJ/mol

(b)

the electron affinity of S+

kJ/mol

(c)

the ionization energy of Cl−

kJ/mol

(d)

the ionization energy of Cl

kJ/mol

(e)

the electron affinity of Cl+

kJ/mol

Successive Ionization Energies in Kilojoules per Mole for the Elements in Period 3 General increase 13 14 Element 11 12 I. 16

Explanation:

Answer:

valence electrons

Explanation:

The valence electrons are the outer most electrons and the principal energy level in which they belong will vary for .

The chemical element which contains four (4) electrons in its third and outer main energy level is: Silicon (Si).

An electron shell can be defined as the outermost shell of an atom of a chemical element around the atomic nucleus.

Hence, an electron shell is an orbital that is typically accompanied by electrons around the nucleus of an atom.

A sublevel is also referred to as an orbital and it can be defined as an energy level that is associated with the electrons found outside the atomic nucleus.

In Chemistry, there are four main (4) types of sublevel and these are:

In the third (3rd) energy level, there are only three (3) sublevels and these are; s, p and d sublevels.

Silicon is a chemical element that is found in group (4) of the periodic table because it has four (4) electrons in its third and outermost shell.  

In its ground state, Silicon (Si) contains the following number of electrons:

Read more: https://brainly.com/question/18214726

Answer:

2.28 atm

Explanation:

V₁ = 2.33L,  V₂ = 1.08L

T₁ = 289K,  T₂ = 304K

P₁ = 1.05 atm, P₂ = ?

Where V₁ and V₂ are initial and final volume respectively

T₁ and T₂ are initial and final temperature respectively

P₁ and P₂ are initial and final pressure respectively

The formula to be used here is the general gas equation:

P₁V₁/T₁=P₂V₂/T₂

1.05 × 2.23/289 = P₂ × 1.08/304

P₂ × 1.08 × 289 = 1.05 × 2.23 × 304

P₂ = (1.05 × 2.23 ×304) ÷ (1.08 × 289)

P₂ = 711.82 ÷ 312.12

P₂ = 2.28 atm

Answer:

C2H6

Explanation:

Let us first consider the molar Masses of each gas

HBr - 80.91 g/mol

NO2 - 46.0055 g/mol

C2H6 - 30.07 g/mol

We must remember that the greater the molar mass of a gas the lesser its velocity and average kinetic energy.

Looking at the gases listed, C2H6 have the highest average kinetic energy at this temperature since it has the lowest molecular mass. This reasoning is directly derived from Graham's law of diffusion in gases.

Hence C2H6 will effuse fastest when a hole is made in the container. It also possess the greatest average kinetic energy because it has the lowest molecular mass.

Answer:

heat is mesured in calories and also joules

Explanation:

Answer:

53/26Fe = 0/-1,B + 53/27 Co

Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

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

From the question

mass = 15.5 g

density = 6.89 g/mL

We have

[tex]volume = \frac{15.5}{6.89} \\ = 2.249637155...[/tex]

We have the final answer as

Hope this helps you

Answer:

A - Atom ---> molecule or compound.

Answer:

Weather radar is used to locate and track severe storm.

Answer:

C is for carbon and O is for oxygen

Answer:

you can see the empirical formula at the pic

The empirical formula for compound (a) is NiI2, (b) is BaBr2 and (c) is BeS.

Empirical formula of a compound is defined as the simplest whole number ratio of atoms present in a compound.

(a) 1.245 g Ni : 5.381 g I

Mole of Ni ; Mole of I = 1.245/59 : 5.381/127 = 0.02 : 0.04 = 1:2

So the formula is NiI2

(b) 2.677 g Ba : 3.115 g Br

Mole of Ba : Mole of Br = 2.677/137 : 3.115/60 = 0.019 : 0.038

= 0.02 : 0.04 = 1:2

So the formula is BaBr2

(c) 2.128 g Be : 7.557 g S

Mole of Be : Mole of S = 2.128/9 : 7.557/32 = 0.2 : 0.2 = 1:1

So the formula is BeS

Thus, empirical formula for compound (a) is NiI2, (b) is BaBr2 and (c) is BeS.

To learn more about empirical formula, refer to the link below:

https://brainly.com/question/11588623

#SPJ2

Answer:

2 double bonds 2 single bonds

Answer:

To get a boy to like you you have to 1.dress up cutely  

2.talk to him ask him what he likes

3. wear a little bit of make-up not to much

4. wear you hair down and have a little bit of hair on your chest

5. Be really confident and don't wait till a really longg time and mess up like i did.

Explanation:

Answer:

Put your hair down. Also, dont use too much makeup. Just wear mascara and lipgloss. Be kind. Be confident.

Explanation:

If u wear to much makeup he will think ur a try-hard. Stop trying to be cool, it's just dumb. If ur rude, then hes gonna think that u dont like him.

Answer:

electron shell is the answer

Answer:

[tex]Cu_2O[/tex]

Explanation:

Hello.

In this case, since the reaction obeys the law of conservation of mass, since the initial oxide had a mass of 0.500 g and yielded 0.444 g of copper, the mass of oxygen in the oxide is:

[tex]m_O=0.500g-0.444g=0.056g[/tex]

In such a way, we next compute the moles of copper and oxygen by using their atomic masses:

[tex]n_{Cu}=0.444g*\frac{1mol}{63.546 g} =0.00699mol\\\\n_O=0.056g*\frac{1mol}{16.00g}=0.0035mol[/tex]

Next, in order to compute the subscripts of Cu and O on the empirical formula we divide the moles by the fewest moles, in this 0.0035 mol as shown below:

[tex]Cu:\frac{0.00699}{0.0035} =2\\\\O:\frac{0.0035}{0.0035} =1[/tex]

It means that the empirical formula turns out:

[tex]Cu_2O[/tex]

Best regards!

Answer:

Mercury Atom

Explanation:

If you are talking about what has 121 neutrons and 80 electrons, then it would be a Mercury Atom. Hope this helps!

Answer:

0.307

Explanation:

use the formula of n=mass /molar mass

Answer:

Heterogeneous mixture

Explanation:

Soil is composed of small pieces of a variety of materials, so it is a heterogeneous mixture.

Answer:

[tex]p=26683.2Pa[/tex]

Explanation:

Hello,

In this case, since the pressure is computed via:

[tex]p=h*\rho*g[/tex]

Whereas h is the 0.520-m height, [tex]\rho[/tex] is the 13600-kg/m³ density and the g the 9.81-m/s² gravity. Thus, the pressure in Pa is:

[tex]p=0.20m*13,600 \frac{kg}{m^3} *9.81\frac{m}{s^2} \\\\p=26683.2\frac{kg*\frac{m}{s^2} }{m^2} =26683.2\frac{N}{m^2}\\ \\p=26683.2Pa[/tex]

Best regards.

Answer:

Water molecules are polar, so they form hydrogen bonds. This gives water unique properties, such as a relatively high boiling point, high specific heat, cohesion, adhesion and density.

EXPLANATION :

So it is unusual for water to be a liquid at room temperature! Water is liquid at room temperature so it's able to move around quicker than it is as solid, enabling the molecules to form fewer hydrogen bonds resulting in the molecules being packed more closely together.

Answer:

[tex]5H_2O+C_5H_{10}O_5\rightarrow 5CO_2+20H^++20e^-[/tex]

Explanation:

Hello.

In this case, when ribose (C₅H₁₀O₅) yields carbon dioxide (CO₂) we write:

[tex]C_5H_{10}O_5\rightarrow CO_2[/tex]

Which needs to be balanced by adding water and hydrogen ions:

[tex]5H_2O+C_5H_{10}O_5\rightarrow 5CO_2+20H^++20e^-[/tex]

You can also see that there are 20 transferred electrons, since the carbon atoms in the ribose have 0 as their oxidation state and the carbon atoms in the carbon dioxide have +4 as the oxidation state, thus, each carbon transfers  4 electrons, a five carbon atoms transfer 20 electrons overall.

In such a way, since the carbon is increasing its oxidation state, such half reaction is an oxidation half reaction.

Best regards.

Answer:

33

Explanation:

Answer:

ΔU = −55.45 kJ

Explanation:

From first law of thermodynamics in chemistry, we have;

ΔU = Q + W

where;

ΔU is change in internal energy

Q is the net heat transfer

W is the net work done

We are given;

Q = 74.6 kJ

But Q will be negative since heat is released

Thus;

ΔU = -74.6 kJ + W

We are given;

Constant pressure; P = 35 atm = 35 × 101325 = 3546375 N/m²

Volume before reaction; Vi = 8.2 L = 0.0082 m³

Volume after reaction; V_f = 2.8 L = 0.0028 m³

Now,

W = -P(V_f - V_i)

W = - 3546375(0.0028 - 0.0082)

W = 19.15 KJ

Thus;

ΔU = Q + W

ΔU = -74.6 kJ + 19.15 KJ =

ΔU = −55.45 kJ