A student measures the length of two pieces of paper as 8.21 in
and 8.0 in. What is the total length? Be sure to use sig. figs. in
your answer. Do not include the unit.

J.J. Thomson's plum pudding model of the atom followed the discovery of negatively charged particles with a very small mass. Thus, the correct option for this question is A.

J.J. Thomson was a British physicist who discovered sub-atomic particles known as electrons within an atom. He also announced that atoms are made up of smaller components.

The plum pudding model is defined by Thomson in order to demonstrate that negatively charged sub-atomic particles known as electrons are surrounded by a volume of positively charged particles known as protons. It is one of the historical scientific model of the atom that governs all sorts of properties of sub-atomic particles.

Therefore, "negatively charged particles with a very small mass" is the discovery that follows J.J. Thomson's plum pudding model of the atom. Thus, the correct option for this question is A.

To learn more about the Plum pudding model, refer to the link:

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Answer:

It is A.

Explanation:

I took the test.

The Lewis structure shows the arrangement of valence electrons in H3PO4.

The Lewis structure gives us a picture of the number of valence electrons in a molecule. This is because, in a Lewis structure, the electrons in the molecule are shown as dots. A single line may be used to show shared electrons in a covalent bond.

The correct Lewis structure of H3PO4 is an upper P is single bonded above to an O, and to the left, right, and below to an O single bonded to an H. The O above the P has three pairs of dots to the left, above, and below; the O's to the sides have pairs of dots above and below, and the O below the P has pairs of dots right and left.

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a. P=0.971 atm=737.6 mmHg

b. n=2.88 x 10⁻³

Dalton's law of partial pressures states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases

[tex]\tt P_T=P_1+P_2+..P_n[/tex]

A. vapor pressure of water at 22.5 = 20.4 mmHg

Pt=P H₂ + P H₂O

758 = P H₂ + 20.4

P H₂=737.6 mmHg=0.971 atm

B.Ideal gas Law = PV=nRT

P = 0.971 atm

V = 72 ml = 0.072 L

R = 0.082 L/atm mol

T = 22.5 + 273.15 =295.65

[tex]\tt n=\dfrac{0.971\times 0.072}{0.082\times 295.65}=2.88\times 10^{-3}[/tex]

Answer:

Gneiss forms by regional metamorphism from both high temperature and pressure. Quartzite and marble are the most commonly used metamorphic rocks.

The empirical formula : C₁₂H₁₇N₂O₄P

The empirical formula is the smallest comparison of atoms of compound =mole ratio of the components

The principle of determining empirical formula

[tex]\tt \dfrac{50.7}{12}=4.225[/tex]

[tex]\tt \dfrac{6.03}{1}=6.03[/tex]

[tex]\tt \dfrac{9.86}{14}=0.704[/tex]

[tex]\tt \dfrac{22.51}{16}=1.407[/tex]

[tex]\tt \dfrac{10.9}{31}=0.352[/tex]

Divide by the smallest mole ratio(0.352)

C : H : N : O : P

[tex]\tt C\rightarrow \dfrac{4.225}{0.352}=12[/tex]

[tex]\tt H\rightarrow \dfrac{6.03}{0.352}=17[/tex]

[tex]\tt N\rightarrow \dfrac{0.704}{0.352}=2[/tex]

[tex]\tt O\rightarrow \dfrac{1.407}{0.352}=4[/tex]

[tex]\tt P\rightarrow \dfrac{0.352}{0.352}=1[/tex]

Answer:

The correct option is the last option (Some dissolved solids may be nonelectrolytes)

Explanation:

Total dissolved solids (TDS) cannot be calculated by conductivity alone because conductivity involves ionic charges and there are solids that dissolve in water but do not carry ionic charges (and thus form non-electrolytes). Examples include sucrose (common sugar) and glucose. These two solids will dissolve in water but would not form ions that will carry ionic charges which are responsible for conductivity. Thus, if TDS only depends solely on conductivity, then a solution that contains dissolved sucrose will be wrongly accounted for as the sucrose will be omitted from the dissolved substances.

A valid reason why total dissolved solids (TDS) cannot be accurately

calculated by conductivity alone because some dissolved solids may be

non-electrolytes.

Conductivity means the ability of electric current to pass through a

substance and an electrolyte has a high conductivity when dissolved in

water.

Dissolved solids can't be measured by conductivity because not all

dissolved solids are electrolytes.

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Answer:

idek akxkkwskkd nwkdkekekd

Answer:

I ordered the tiles from left to right and top to bottom as the numbers kept increasing. The tiles were also organized based on the color and shape that they were. The tiles with the same color and shape were arranged in the same column.

Explanation:

In the modern periodic table, the elements are listed in order of increasing atomic number and elements having similar chemical properties naturally line up in the same column (group).

Answer:

[tex]M_2=3.34x10^{-3}M[/tex]

Explanation:

Hello!

In this case, since a dilution process implies that the moles of the solute remain the same before and after the addition of diluting water, we can write:

[tex]M_1V_1=M_2V_2[/tex]

Thus, since we know the volume and concentration of the initial sample, we compute the resulting concentration as shown below:

[tex]M_2=\frac{M_2V_2}{V_1} =\frac{45.45mL*0.0404M}{550.00mL}\\\\M_2=3.34x10^{-3}M[/tex]

Best regards!

Answer:

please brainlist answer

Explanation:

The addition of K 3 Fe(CN) 6 to a solution causes the formation of a deep blue precipitate which indicates that iron(II) ions are present.

The conclusive test for iron(II) ions is the test by the use of potassium hexacyanoferrate III solution.

In qualitative analysis certain reagents are used to test for the presence of certain cations or anions. Those reagents react in a certain way with those reagents. Usually, a positive test may involve a color change, formation of a precipitate or evolution of a gas.

In the case of iron(II) ions, potassium hexacyanoferrate III solution is used in the conclusive qualitative test for the ion. A positive test involves the appearance of a deep blue precipitate.

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Answer:

True

Explanation:

Mixtures are substances with indefinite composition. They consist of two or more elements  and or compounds in any proportion by mass.

From these properties we can clearly identify that to separate mixtures, we use the differences in the chemical properties of the constituents of the mixtures.

Answer:

None. Electrons are not in the nucleus.

Explanation:

We know that an atom consist of electrons, protons and neutrons. Neutrons and protons are present inside the nucleus while electrons are present out side the nucleus. Electron has a negative charge and is written as e⁻. The mass of electron is 9.10938356×10⁻³¹ Kg . While mass of proton and neutron is 1.672623×10⁻²⁷Kg and 1.674929×10⁻²⁷ Kg respectively.

Symbol of proton= P⁺  

Symbol of neutron= n⁰  

The number of electron or number of protons are called atomic number while mass number of an atom is sum of protons and neutrons. The umber of protons and electrons are always equal to make the atom electrically neutral .

The atom having atomic number 16 have 16 electrons and these electrons are present out side the nucleus.

Answer:

C

Explanation:

Answer:

I think is A

Explanation:

Hope it helps

Answer:

2H⁺ (aq) + 2OH⁻ (aq) → 2H₂O (l)

General Formulas and Concepts:

Explanation:

Step 1: RxN

HNO₃ (aq) + Ca(OH)₂ (aq) → Ca(NO₃)₂ (aq) + H₂O (l)

Step 2: Balance RxN

2HNO₃ (aq) + Ca(OH)₂ (aq) → Ca(NO₃)₂ (aq) + 2H₂O (l)

Step 3: Ionic Equations

Total Ionic Equation:

2H⁺ (aq) + 2NO₃⁻ (aq) + Ca²⁺ (aq) + 2OH⁻ (aq) → Ca²⁺ (aq) + 2NO₃⁻ (aq) + 2H₂O (l)

Cancel out spectator ions.

Net Ionic Equation:

2H⁺ (aq) + 2OH⁻ (aq) → 2H₂O (l)

Answer:

167 mL.

Explanation:

We'll begin by calculating the number of moles in 45 g of aluminum (Al). This can be obtained as follow:

Mass of Al = 45 g

Molar mass of Al = 27 g/mol

Mole of Al =?

Mole = mass /Molar mass

Mole of Al = 45/27

Mole of Al = 1.67 moles

Next, the balanced equation for the reaction. This is given below:

2Al + 3H2SO4 → Al2(SO4)3 + 3H2

From the balanced equation above,

2 moles of Al reacted with 3 moles of H2SO4.

Next, we shall determine the number of mole of H2SO4 needed to react with 45 g (i.e 1.67 moles) of Al. This can be obtained as:

From the balanced equation above,

2 moles of Al reacted with 3 moles of H2SO4.

Therefore, 1.67 moles of Al will react with = (1.67 × 3)/2 = 2.505 moles of H2SO4.

Thus 2.505 moles of H2SO4 is needed for the reaction.

Next, we shall determine the volume of H2SO4 needed for the reaction. This can be obtained as follow:

Molarity of H2SO4 = 15.0 M

Mole of H2SO4 = 2.505 moles

Volume =?

Molarity = mole /Volume

15 = 2.505 / volume

Cross multiply

15 × volume = 2.505

Divide both side by 15

Volume = 2.505/15

Volume = 0.167 L

Finally, we shall convert 0.167 L to mL. This can be obtained as follow:

1 L = 1000 mL

Therefore,

0.167 L = 0.167 L × 1000 mL / 1 L

0.167 L = 167 mL

Thus, 0.167 L is equivalent to 167 mL.

Therefore, 167 mL H2SO4 is needed for the reaction.

Answer:

Microscope

Explanation:

Answer:

its a telescope you see stars or plants

Explanation:

Answer:

Trioxocarbonate (iv) are salts derived from trioxocarbonate (iv) acid when it reacts with metals and metallic oxides. All trioxocarbonate (iv) salts of Sodium (Na), Potassium (K) and Ammonium(NH4+) are soluble while all others are insoluble.

Answer:

Topographical

Explanation:

When it comes to questions such as this one, the thing that could help you the most is a dictionary. A dictionary is an alphabetically arranged listing of words that contains various information about those words, such as their definitions, examples, origin, pronunciation, etc.

The term the given definition refers to is topographical. Topography is the study of the forms and features of land surfaces. The topography of an area refers to its physical properties and terrain or their description (e.g. how they're shown on a map).

Answer:

Zamir walked

27

meters and Talia walked

19

meters.

Explanation:

27 and 19

Answer:

zamir:27  Talia:19

Explanation:

i got it right on my test :)

Answer:

A

Explanation:

The 12 stands for the number of electrons that fill the f orbital

In an atom there are levels of energy in the shell and sub shell  

This energy level is expressed in the form of electron configurations.  

Writing electron configurations starts from the lowest to the highest sub-shell energy level. There are 4 sub-shells in the shell of an atom, namely s, p, d and f. The maximum number of electrons for each sub shell is  

• s: 2 electrons  

• p: 6 electrons  

• d: 10 electrons and  

• f: 14 electrons  

4f¹² :

4 : number of shell

12 : the number of electrons that fill the f orbital

Answer:

a. Approximately [tex]1.3\; \rm mL[/tex].

b. Approximately [tex]7.2\; \rm mL[/tex].

Explanation:

The unit of concentration "[tex]\rm M[/tex]" is equivalent to "[tex]\rm mol \cdot L^{-1}[/tex]", which means "moles per liter."

However, the volume of both solutions were given in mililiters [tex]\rm mL[/tex]. Convert these volumes to liters:

[tex]\displaystyle 45\; \rm mL = 45\; \rm mL \times \frac{1\; \rm L}{1000\; \rm mL} = 0.045\; \rm L[/tex].

[tex]\displaystyle 330\; \rm mL = 330\; \rm mL \times \frac{1\; \rm L}{1000\; \rm mL} = 0.330\; \rm L[/tex].

In a solution of volume [tex]V[/tex] where the concentration of a solute is [tex]c[/tex], there would be [tex]c \cdot V[/tex] (moles of) formula units of this solute.

Calculate the number of moles of [tex]\rm NaCl[/tex] formula units in each of the two solutions:

Solution in a.:

[tex]n = c \cdot V = 0.045\; \rm L \times 0.10\; \rm mol \cdot L^{-1} = 0.0045\; \rm mol[/tex].

Solution in b.:

[tex]n = c \cdot V = 0.330\; \rm L \times 0.074\; \rm mol \cdot L^{-1} = 0.02442\; \rm mol[/tex].

What volume of that [tex]3.4\; \rm M[/tex] (same as [tex]3.4 \; \rm mol \cdot L^{-1}[/tex]) [tex]\rm NaCl[/tex] solution would contain that many

For the solution in a.:

[tex]\displaystyle V = \frac{n}{c} = \frac{0.0045\; \rm mol}{3.4\; \rm mol \cdot L^{-1}} \approx 0.0013\; \rm L[/tex].

Convert the unit of that volume to milliliters:

[tex]\displaystyle 0.0013\; \rm L = 0.0013\; \rm L \times \frac{1000\; \rm mL}{1\; \rm L} = 1.3\; \rm mL[/tex].

Similarly, for the solution in b.:

[tex]\displaystyle V = \frac{n}{c} = \frac{0.02442\; \rm mol}{3.4\; \rm mol \cdot L^{-1}} \approx 0.0072\; \rm L[/tex].

Convert the unit of that volume to milliliters:

[tex]\displaystyle 0.0072\; \rm L = 0.0072\; \rm L \times \frac{1000\; \rm mL}{1\; \rm L} = 7.2\; \rm mL[/tex].

Answer:

Copper, a metal known since ancient times, is used in electrical cables and pennies, among other things. ... Calculate the average atomic mass of copper. ... The atomic masses of the two stable isotopes of boron 10B (19.78%) and 11B (80.22%) are 10.0129 amu ... (.1978)(10.0129 amu) + (.8022)(11.0093 amu) =10.81 amu.

Explanation:

I hope I help :)

Answer:

Mass is conserverd

Explanation:

Any chemical reaction must follow the law of conservation of mass. Meaning that mass cannot be created nor destroyed. Since all chemical reactions must follow this law, no matter what reaction happens, mass is conserved.

if you just look up the answer it comes up btw!!

have a great day

Answer:

Warm Water

Explanation:

In warm temperatures, cold-blooded animals are more active and can travel more quickly. This occurs because heat activated reactions provide energy to move muscles. In the absence of heat the animal becomes slow and sluggish. So they are usually inactive and rest when it is cold. As they do not need to feed much, they spend less time looking for food, so this life strategy works for them.

Brainliest?

Answer warm water Explanation:i have the same question

Answer:

The wavelength of the energy that needs to be absorbed  = 52.36 nm

Explanation:

For this study;

Let consider the Rydgberg equation from Bohr's theory of atomic model:

i.e.

[tex]\dfrac{1}{\lambda} = R_H (Z^*)^2( \dfrac{1}{n_1^2}-\dfrac{1}{n_2^2})[/tex]

where

Z* = effective nuclear charge of atom = Z - σ = 6

n₁ = lower orbit = 3

n₂ = higher orbit = 4

[tex]R_H[/tex] = Rydyberg constant = 1.09 × 10⁷ m⁻¹

λ = wave length of the light absorbed

∴

[tex]\dfrac{1}{\lambda} = 1.09 \times 10^7}(6)^2( \dfrac{1}{3^2}-\dfrac{1}{4^2})[/tex]

[tex]\dfrac{1}{\lambda} = 1.09 \times 10^7}(36)( \dfrac{1}{9}-\dfrac{1}{16})[/tex]

[tex]\dfrac{1}{\lambda} = 392400000\times0.0486111111[/tex]

[tex]\dfrac{1}{\lambda} =19075000[/tex]

[tex]\lambda = \dfrac{1}{19075000}[/tex]

[tex]\lambda = \dfrac{1}{1.91\times 10^7 \ m^{-1}}[/tex]

[tex]\lambda = 5.236 \times 10^{-8} m[/tex]

[tex]\lambda = 52.36 \times 10^{-9} m[/tex]

[tex]\lambda = 52.36\ n m[/tex]

Therefore, the wavelength of the energy that needs to be absorbed  = 52.36 nm