Which sample is a pure substance?zinc oxidesugar dissolved in waterpond watersoil.

Answer:

4

Explanation:

Elements in group 14 have 4 valence electrons. Meaning that to achieve a stable octet they need to either gain or lose 4 electrons in total.

Answer:

see answer

Explanation:

DO the postulates of Daltons atomic theory explain the law of conservation of mass and the law of constant composition.

1. Everything is composed of atoms, which are the indivisible building blocks of matter and cannot be destroyed or divided any further.

2. All atoms of a single pure element are the same in size and mass

3. Atoms of different elements vary from each other in size and mass.

4. Compounds are produced through different simple whole-number combinations of atoms to produce molecules.  

5. Anywhere a compound exists, it will have the same atoms in the same ratio.

6. A chemical reaction between compounds is a re-arrangement of atoms

The law of conservation of mass is shown in 2, 4. and 5.

The law of constant co,position is shown in 2, 4, 5, and 6

Answer:

Copper is reddish brown color

Its density is 8.93 g cm-3

highly malleable at ordinary temp, but is brittle near its melting point

god conductor of heat and electricity

Explanation:

Answer:

the same number of atomic orbitals.

Explanation:

Answer:

All of the elements in a period have the same number of atomic orbitals. For example, every element in the top row (the first period) has one orbital for its electrons. All of the elements in the second row (the second period) have two orbitals for their electrons.

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Answer:

One arrow is positioned in each box according to Hund's Rule which tells us to maximise the number of unpaired electrons in orbitals of the same subshell, and, to give those electrons the same "spin" (parallel spin).

Explanation:

Answer:

specific heat capacity of the unknown is 629.66 J/kg C

Explanation:

As we know that gold is heated to 72.3 degree C and mixed with water at 24.8 degree C

Now the final temperature of the mixture is 26 degree C

here we can say that heat given by the gold = heat absorbed by the water

So we will have

Q_{in} = Q_{out}Q

in

=Q

out

2.62 s (72.3 - 24.8) = 15.6 (4186) (26 - 24.8)2.62s(72.3−24.8)=15.6(4186)(26−24.8)

so we will have

s = 629.66 J/kg Cs=629.66J/kgC

so specific heat capacity of the unknown is 629.66 J/kg C

Answer:

36. B, LATTICE

35. A, COVALENT

38. B, TRIPLE COVALENT

Explanation:

36: Lattice- Sodium chloride is taken as a typical ionic compound.

35. covalent - the interatomic linkage that results from the sharing of an electron pair between two atoms. The binding arises from the electrostatic attraction of their nuclei for the same electrons.

38. TRIPLE COVALENT- because each nitrogen atom needs three electrons to fill its outermost shell.

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I hope it help

NaCl has a cubic unit cell, best thought of as a face-central cubic array of anions with an interpenetrating FCC action lattice or (vice versa). The cell looks the same whether you start with anions or cations on the corners. Each ion is 6 co-ordinates and has a local octahedral geometry.

NaCl lattice exhibit  cubic unit cell.  The face-centered cubic array of anions with an interpenetrating fcc cation lattice are seen in 3D structure. Each ion is 6-coordinate and has a local octahedral geometry.

Sodium chloride is an ionic compound, formed from the sodium metal and chlorine atom. The ionic bond is formed by loss of one electron from sodium metal to the chlorine atom.

The lattice structure of all metals contains a pool of cations in the sea of mobile electrons.  The electrons can be delocalized into the interstices and thus metals conduct electrically and thermally.

In the fcc lattice of NaCl,  sodium atoms are arranged at the corners and Cl atoms are at the center of each cube face of the cell. They are assumed to touch along face diagonals.

Atoms are arranged at the corners of the cube with another atom at the cube center also hence there will 4 atoms one unit cell.

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Answer:

1.51e23 atoms

Explanation:

First, using the molar mass of Si (28.1 g/mol), determine the # of moles of Si we have. Then use Avogadro's number (6.022e23 atoms = 1 mol) to convert the # of moles to the # of Si atoms.

(7.02 g Si)([tex]\frac{1 mol}{28.1 g}[/tex]) = 0.250 mol Si              

(0.250 mol Si)([tex]\frac{6.022*10^{23} atoms }{1 mol}[/tex]) = 1.51e23 atoms    

The atomic mass of Silicon (Si) is 28.09 g/mol. The no. of atoms present in 7.02 g of Si is 1.46 × 10²³.

Any substance containing  6.022 × 10²³ atoms is called one mole of that substance.  The no.of moles can be calculated by dividing the given weight by the atomic mass of the substance.

Atomic mass of Si = 28.09 g/mol

      Given mass    = 7.02 g.

       No.of moles  = 7.02 g/ 28.09 g/mol

                             = 0.24 moles

One mole contains  6.02 × 10²³ atoms. Thus 0.24 mole of Si contains  6.02 × 10²³ × 0.24  = 1.46 × 10²³ atoms.

Hence, no.of atoms present in 7.02 g of Si is 1.46 × 10²³ .

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Answer:

Our body loses heat by the evaporation of sweat, which is like a tea kettle boiling on a stove top. Both are being heated through conduction, the tea kettle from the stove top and the sweat from our body.

Explanation:

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Answer:

0.296 M

Explanation:

What is the molar concentration of a solution prepared by dissolving 3.05 grams of sodium acetate in enough water to prepare 3.43 x 102 mL of the solution

sodium acetate NaCH3COO has molar mas of

23 + 12 +24 + 1 +32 = 92 g/mol

3.05 g is 3.05 g/ 92 g/mol = 0.0328 moles

it is distributed over 102 mL = 0.102 L

its concentration is 0.0328/ 0.102 =0.296 M Mhttps://brainly.com/question/25586315?answering=true&answeringSource=feedPublic%2FhomePage%2F3#

Answer:

How to Write the Net Ionic Equation for H2SO4 + MgCO3 = MgSO4 + H2O + CO2 -

A net ionic equation also contains the spectator ions, whereas a net ionic equation just displays the chemical species that are involved in a process.

H₂SO₄ (aq) + MgCO₃ (s) →H₂O (l) + CO₂(g) + MgSO₄(aq)  

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Answer:

Cells are the basic structural unit of all living organisms.

Explanation:

Hope this helps, but i'm unsure if it would be multiple choice or not.

A chemical reaction is a process that can lead to a change of state, the outcome of a chemical reaction can ultimately lead to the formation of a new substance.

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Air is mixture.

But pure air compound .

Explanation:

So the answer is Compound.

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Answer:

D. Plasma

Explanation:

Answer:

They collect all of the evidence for cases

Explanation:

the answer is using rollers in conjunction with inclined plane.

Answer:

Prokaryotic cell

Explanation:

If you search it up you will see that the prokaryotic cell looks exactly alike with the picture you have posted.

Answer:6.42 ppm

Explanation:ppm = (g soluto/g soluzione) ×1000000

Answer:

Explanation:

The new volume can be found by using the formula for Boyle's law which is

[tex]V_2 = \frac{P_1V_1}{P_2} \\[/tex]

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

From the question we have

[tex]V_2 = \frac{700 \times 120}{1500} = \frac{84000}{1500} = \frac{840}{15} \\ = 56[/tex]

We have the final answer as

Hope this helps you

Answer:

5.57 x 10^24 atoms

Explanation:

first, you are seeking the number of ATOMS of Boron.

Boron has an Atomic mass of 10.8 g/mol (see #5 on the periodic table)

100 gm of Boron would have 100 g /10.8 g/mol =9.26 moles

each mole has Avogadros number of atoms 6.02 x 10^23

9.26 moles has 9.26 x 6.02 x 10^23 atoms =5.57 x 10^24 atoms

Bond number

The characteristic of reactions that depends on valence electrons is the bond type.

In chemistry, a chemical bond could be;

Ionic

Covalent

The type of bond formed depends on the number of valence electrons present. When there are few valence electrons on an atom, it mostly forms ionic bonds.

When there are more electrons on an atoms, it mostly forms covalent bonds and the electrons between the atoms are shared.

Answer: 82.0 g/mole

Explanation:

Use the units to see that if we divide 1.64 grams by 0.0200 moles, we'll get a number that is grams/mole, the definition of formula mass.

1.64/0.0200 = 82.0 g/mole (3 sig figs)

We can't tell from this alone what the molecular formula might be, but C6H10 (cyclohexene) comes close (82.1 grams/mole).

The formula mass of the compound will be approximately 82.0 g/mol

The formula mass of the compound is the sum of atomic masses of all the atoms in its chemical formula. It is calculated by adding up the atomic masses of the individual elements in the compound, each multiplied by the subscript indicating the number of atoms of that element in the formula.

To find the formula mass of the compound, we'll use the relationship between moles, mass, and molar mass.

Molar mass (in g/mol) = Mass (in g)/Moles

Given:

Mass = 1.64 g

Moles = 0.0200 moles

Let's plug the values and calculate molar mass:

Molar mass = 1.64 g / 0.0200 moles

Molar mass ≈ 82.0 g/mol

The formula mass of the compound is approximately 82.0 g/mol, rounded to three significant figures.

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Answer:

Reforestation can be used to undo and rectify the effects of deforestation and improve the quality of human life by absorbing pollution and dust from the air, rebuilding natural habitats and ecosystems,reducing global warming via biosequestration of atmospheric carbon dioxide, and harvesting for resources, particularly.

Explanation:

Answer:

96mg

Explanation:

Since the half-life of Palladium-100 is 4 days and the sample has been reduced after 16 days, that means the sample has undergone four half-lives. To find the intial mass, just work backwards:

As you see, I've worked backwards from the four half-lives. So the initial mass after 16 days is 96 mg.

Answer:

welp it would be this option : Move the decimal in 85 TWO places to the right to decrease the value.

Explanation:

Answer:

Option A

Explanation:

Moving the decimal point 2 places to the right will give you 8500 cm=85m

[tex]\begin{gathered}\boxed{\begin{array}{c}\\ {\pmb{\sf{Three \: equation \: of \: motion}}} \\ \\ \sf \star \: v \: = u \: + at \\ \\ \sf \star \: s \: = ut + \: \dfrac{1}{2} \: at^2 \\ \\ \sf \star \: v^2 - u^2 \: = 2as\end{array}}\end{gathered}[/tex]

[tex]\pink{\qquad \pmb{ \sf\longrightarrow v \: = u \: + at}}[/tex]

[tex] \qquad \pmb{\sf \longrightarrow v = 0 + 2.5 \times 2}[/tex]

[tex]\qquad \pmb{ \sf\longrightarrow v = 0 + 5}[/tex]

[tex] \qquad \pmb{\sf \longrightarrow v = 5 \: ms^{-1}}[/tex]

[tex]\qquad \longrightarrow {\pink{\underline{\underline{\pmb{\sf{ Final \: velocity= 5 \: ms^{-1} }}}}}}[/tex]

Henceforth –

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Answer:

Explanation:

b