How many significant figures are in the number 4.02 x 10^-9 ?

Answer:

20 and 24 are chemical the rest are physical

Answer:

1. Fireworks: chemical,

2. Hair: physical

3. glow sticks: chemical

4.Baseball: physical

5.Popcorn: chemical

Explanation:

1. bc there are chemicals/powders

2. the hair is still hair, even if it is cut

3. You are combining chemicals, this cannot be un-done

4. The shards are still glass, they do not turn into another substance other than glass

5. You heated the popcorn, it "exploded", this cannot be undone

Answer:

Break apart

Explanation:

Decompose: to break down or cause to break down into component elements or simpler constituents.

Answer:

[tex]186.5\ \text{K}[/tex]

Explanation:

[tex]V_1[/tex] = Initial volume = 0.05 L

[tex]V_2[/tex] = Final volume = 0.1 L

[tex]T_1[/tex] = Initial temperature

[tex]T_2[/tex] = Final temperature = 373 K

From the ideal gas law we have

[tex]PV=nRT[/tex]

So

[tex]V\propto T[/tex]

[tex]\dfrac{V_1}{V_2}=\dfrac{T_1}{T_2}\\\Rightarrow T_1=\dfrac{V_1}{V_2}\times T_2\\\Rightarrow T_1=\dfrac{0.05}{0.1}\times 373\\\Rightarrow T_1=186.5\ \text{K}[/tex]

The intial temperature is [tex]186.5\ \text{K}[/tex].

Answer: % yield

=

actual yield

theoretical yield

⋅

100

%

So, let's say you want to do an experiment in the lab. You want to measure how much water is produced when 12.0 g of glucose (

C

6

H

12

O

6

) is burned with enough oxygen.

C

6

H

12

O

6

+

6

O

2

→

6

C

O

2

+

6

H

2

O

Since you have a

1

:

6

mole ratio between glucose and water, you can determine how much water you would get by

12.0

g glucose

⋅

1 mole glucose

180.0 g

⋅

6 moles of water

1 mole glucose

⋅

18.0 g

1 mole water

=

7.20

g

This represents your theoretical yield. If the percent yield is 100%, the actual yield will be equal to the theoretical yield. However, after you do the experiment you discover that only 6.50 g of water were produced.

Since less than what was calculated was actually produced, it means that the reaction's percent yield must be smaller than 100%. This is confirmed by

% yield

=

6.50 g

7.20 g

⋅

100

%

=

90.3

%

You can backtrack from here and find out how much glucose reacted

65.0 g of water

⋅

1 mole

18.0 g

⋅

1 mole glucose

6 moles water

⋅

180.0 g

1 mole glucose

=

10.8

g

Explanation:

Answer:no answer,

Explanation: but if the other dude see this can you re word Wht u said it’s hard to make sense of it

Answer:

the chemical element of atomic number 16, a yellow combustible nonmetal.

Explanation:

ur welcome plz give me brainliest

Explanation:

A pale-yellow, brittle nonmetallic element that occurs widely in nature, especially in volcanic deposits, minerals, natural gas, and petroleum. It is used to make gunpowder and fertilizer, to vulcanize rubber, and to produce sulfuric acid.

Answer:

The percent isotopic abundance of Ir-193 is 60.85 %

The percent isotopic abundance of Ir-191 is 39.15 %

Explanation:

we know there are two naturally occurring isotopes of iridium, Ir-191 and Ir-193

First of all we will set the fraction for both isotopes

X for the isotopes having mass 193

1-x for isotopes having mass 191

The average atomic mass is 192.217

we will use the following equation,

193x + 191(1-x) = 192.217

193x + 191 - 191x = 192.217

193x- 191x = 192.217 - 191

2x = 1.217

x= 1.217/2

x= 0.6085

0.6085 × 100 = 60.85 %

60.85% is abundance of Ir-193 because we solve the fraction x.

now we will calculate the abundance of Ir-191.

(1-x)

1-0.6085 =0.3915

0.3915× 100= 39.15 %

The modern periodic table consists of the elements which are arranged in the increasing order of their atomic numbers. The element 'C' belongs to 14th group of the periodic table. The correct option is A.

The orbital diagrams are the pictorial representation of the electrons in an atom. The orbital diagrams are mainly based on the Auf Bau principle, Pauli's exclusion principle and Hund's rule of maximum multiplicity.

According to Auf Bau principle, the electrons are arranged in the orbitals in the increasing order of their energies. The pauli's exclusion principle states that no two electrons in an atom can have the same set of four quantum numbers.

The hund's rule states that the unpaired electrons in the orbitals have parallel spins. The atomic number of 'C' is 6, and its electronic configuration is 1s²2s²2p².

Thus the correct option is A.

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Answer:

Answer

Explanation:

Evidence from fossils, glaciers, and complementary coastlines helps reveal how the plates once fit together. Fossils tell us when and where plants and animals once existed. ... This distribution of fossils led to theories that the southern continents were once joined in a supercontinent called Gondwana.

Answer: Evidence from fossils, glaciers, and complementary coastlines helps reveal how the plates once fit together. Fossils tell us when and where plants and animals once existed.

Explanation: I hoped that helped plzz mark as brainliest !!

Answer: 32.07 g/mole

Explanation:

1 mole of sulfur contains 6.022 ×10^23 atoms

1 mole is equal to 32.07 g

6.022 ×10^23 atoms = 32.07

Answer:

I don't EXACTLY know but hopefully the description below helps you find the answer!

Ionic bonding is a type of chemical bond in which valence electrons are lost from one atom and gained by another. This exchange results in a more stable, noble gas electronic configuration for both atoms involved. An ionic bond is based on attractive electrostatic forces between two ions of opposite charge.

Explanation:

Answer:

E = 3.035× 10-¹⁹J = 1.9eV

f = 4.58 × 10¹⁴Hz

Explanation:

wavelength = 6.55 × 10-⁷m

c = 3 × 10⁸m/s

f = ?

E = ?

a) f = c/wavelength

f = 3 × 10⁸/6.55 × 10-⁷

f = 4.58 × 10¹⁴Hz

b) E = hc/wavelength

E = 6.626×10-³⁴ × 3 × 10⁸/ 6.55 × 10-⁷

E = 3.035 × 10-¹⁹J

1ev = 1.6 × 10-¹⁹J

Therefore E = 3.035/1.6 = 1.9eV

Hope it's not too late man

Each plant organ (roots, stems, leaves) contains all three tissue types: ... Vascular tissue is made of two specialized conducting tissues: xylem and phloem. Xylem tissue transports water and nutrients from the roots to different parts of the plant, and also plays a role in structural support in the stem

PLEASE MARK ME AS BRAINLIEST

Answer:

b

Explanation:

Answer:

The 3rd equation.

Cl2 + 2NaBr —> 2NaCl + Br2

Explanation:

The law of conservation of matter (mass) states that matter can neither be created nor destroyed during a chemical reaction but can be transferred from one form to another. This implies that unbalanced chemical equation shows that matter (mass) has been created or destroyed.

Now, we shall determine which equation is balanced as follow:

1. 2Cl2 + NaBr —> 2NaCl + Br2

Reactant >>>>>>>> Product

4 Cl >>>>>>>>>>>> 2 Cl

1 Na >>>>>>>>>>>> 2 Na

1 Br >>>>>>>>>>>> 2 Br

Thus, the equation is not balanced.

2. Cl2 + NaBr —> NaCl + Br2

Reactant >>>>>>>> Product

2 Cl >>>>>>>>>>>> 1 Cl

1 Na >>>>>>>>>>>> 1 Na

1 Br >>>>>>>>>>>> 2 Br

Thus, the equation is not balanced.

3. Cl2 + 2NaBr —> 2NaCl + Br2

Reactant >>>>>>>> Product

2 Cl >>>>>>>>>>>> 2 Cl

2 Na >>>>>>>>>>> 2 Na

2 Br >>>>>>>>>>>> 2 Br

Thus, the equation is balanced.

From the illustration made above only the 3rd equation is balanced. And this is in line with the law of the Conservation of matter (mass) as matter (mass) was not created nor destroyed during the chemical reaction but was transferred to other forms.

Answer:

I dont think so. If you continue to heat them up they will shrink and dissapper r become ashes. Thats a very interesting question btw. :) hope this helps!

Explanation:

The compounds have been formed by the combination of molecules and atoms. The names are a. aluminum sulfate, b. calcium chloride, c. potassium sulfate, d. potassium nitrate, and e. calcium carbonate.

The chemical formula has been defined as the representation of the chemical compound or molecules with the aid of symbols, letters, and coefficients to show the proportions, arrows, parentheses, signs, etc.

The chemical formulas are named as:

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atomic number 15

1S^2,2S^2,2P^6,3S^2,3P^3

atomic number 12

1S^2,2S^2,2P^6,3S^2

atomic number 9

1S^2,2S^2,2P^5

atomic number 18

1S^2,2S^2,2P^6,3S^2,3P^6

Answer: D. a mixture

Explanation: When you mix different types of nuts or snacks together including raisins, hazelnuts, almonds, and peanuts to make some kind of trail mix, then you are creating a mixture, specifically a heterogeneous mixture.

Answer:

im pretty sure its the second one

Answer:

A. Chemical

B. physical

Explanation:

Answer:

A

Explanation:

When the North Pole of one bar magnet is near the South Pole of another bar magnet, they will attract each other. So, the correct option is C, attraction. This is because opposite magnetic poles attract each other, while like magnetic poles repel each other.

A magnetic field is a region in space where a magnetic force can be detected. It is created by the movement of charged particles, such as electrons, protons, and ions. A magnetic field can be produced by a magnet, an electric current, or a changing electric field.

When the North Pole of one bar magnet is near the South Pole of another bar magnet, they will attract each other. This is because the magnetic field lines of the two magnets interact in such a way that they try to align with each other. Since opposite magnetic poles attract each other, the North Pole of one magnet will be attracted to the South Pole of the other magnet.

The magnetic force between the two magnets depends on the strength of the magnetic field and the distance between the magnets. The closer the magnets are, the stronger the magnetic force will be.

Therefore option C, attraction is correct.

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1. option B

2. ground state Fe :  [Ar] 4s² 3d⁶

Aufbau rule

Electrons occupy orbitals of the lowest energy level

Charging electrons in the sub-shell uses the following sequence:  

1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, 6s², etc.  

So the correct choice of answer is B.

Ground state is the state of electrons filling skins with the lowest energy levels.

Excited state is the state of electrons which occupy a higher energy level

The atomic number of Fe = 26, so electrons=26

Ground state configuration of Fe : [Ar] 4s² 3d⁶ or

1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d⁶

Answer:

d

Explanation:

Answer:

It is an Alkaline Earth Metal

Explanation:

Metallic bonding results from the delocalization of electrons from the parent metal atom so that positive ions are conceived to swim in a sea of electrons. This view of metallic bonding accounts for the malleability, and ductility of metals, as well as their properties of thermal and electrical conduction.

Answer: 116.15 g/mol

Answer:

so you can dress based on how hot or cold it's gonna be outside

Answer:

decomposition of water

Explanation:

The reaction will represent the decomposition of water. It usually carried by an electrolytic process in the laboratory.

Answer:

decomposition of water

Explanation:

i took the quiz and it was right