PLEASE HELPPP !!!!!!!!!!!!!!!!

Answer:

30 molecules

Explanation:

easy

Answer:

It is a liquid gas

Explanation:

The spark of the lighter starts the fire which is exposed to the liquid gas in the lighter

Answer:

Average atomic mass  = 79.9 amu.

Explanation:

Given data:

Average atomic mass of Bromine = ?

Atomic mass of 1st isotope = 78.92 amu

Relative abundance of 1st isotope = 50.69%

Atomic mass of 2nd isotope = 80.92 amu

Relative abundance of 1st isotope = 49.31%

Solution:

Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)  / 100

Average atomic mass  = (50.69×78.92)+(80.92×49.31) /100

Average atomic mass =  4000.45 + 3990.16 / 100

Average atomic mass  = 7990.61 / 100

Average atomic mass  = 79.9 amu.

Answer:

5,778 K

Explanation:

Answer:

G, but I think that theres more than one answer

Answer:

It’s b

Explanation:

Answer:

Regulation of the cell cycle is carried out by which of the following? Check all that apply.

CdKs  

cyclins

What is the role of CdKs?

to signal the cell to move to the next phase of the cell cycle

Explanation:

Answer:

the first one

Explanation:

Answer:

lead , chemical

Explanation:

Answer:

²⁸Mg

Explanation:

12 electrons means it is a Mg;

A typical Mg has 12 neutrons, but this has 16 hence it must be an isotope with 4 extra neutrons.

Answer:

D. formation of zinc from zinc sulphide ​

Explanation:

A redox reaction could be explained as an artificial reaction in which electrons are moved between two reactants partaking in it. This substitution of electrons can be recognized by examining the variations in the oxidation states of the reacting classes. The generation of hydrogen fluoride is an illustration of a redox reaction. We can crack the reaction down to investigate the oxidation and loss of reactants.

Answer:

Burning wood is a chemical change.  Burning wood is an example of a chemical reaction in which wood in the presence of heat and oxygen is transformed into carbon dioxide, water vapour, and ash.

Baking an apple pie is a physical change because the apples in the pie start changing physically and the pie crust starts hardening and rising up.

Explanation:

Answer:

Kinetic energy and potential energy

Explanation:

kinetic energy is when the energy is active and potential energy is when it is about to be active

Explanation:

First, we need to calculate the number of moles of sodium carbonate we have in a 25 g sample. To calculate this, we will

find the molar mass of sodium carbonate (Na2CO3):

⇒ 2 × Molar mass of sodium + Molar mass of carbon + 3×molar mass of oxygen

⇒ 2 × 23 + 12 + 3 × 16

⇒ 46 + 12 + 48

⇒ 106g/mol

Thus, the molar mass of Na2CO3 is 106g/mol.

Therefore, number of moles = 25 ÷ 106

=> 0.2358 mol

Now, we know that every mole of Na2CO3 have 0.2358 moles of Na+ ions. Hence, total moles of Na2CO3 is 0.4716 moles

Number of ions present = 6.022 × 1023 × 0.4716 mol = 2.84 × 1023ions

The molar mass of sodium carbonate is 106 g/mol. One mole of sodium carbonate gives 2 Na+ ions. Thus number of moles in 25 g of sodium carbonate is 0.47 moles.

Sodium ion Na+ is formed by the lose of one electron from the sodium metal. Sodium has one valence electron and it will reacts with other atoms by donating this electron and gaining a positive charge.

The molecular formula of sodium carbonate is Na₂CO₃. Therefore, one mole of sodium carbonate will give two moles of Na+ ions. The molar mass of sodium carbonate is 106 g/mol.

The number of moles of 25 g of sodium carbonate is calculated as follows:

Number of moles = 25 /106

                             =  0.235 moles.

It is clear that one mole of Na₂CO₃ gives two moles of sodium ions.Then, number of moles of sodium ions given by 0.235 moles of sodium carbonate is calculated as follows:

number of moles of Na+ = 0.235 × 2

                                         = 0.47 moles

Hence, the number of moles of Na+ ions produced by 25g of sodium carbonate is 0.47 moles.

To find more about sodium carbonate, refer the link below:

https://brainly.com/question/28901831

#SPJ2

Answer:

P₂ = 261 KPa

Explanation:

Given data:

Volume of sample = 200 mL

Initial pressure = 110 KPa

Initial temperature = 275 K

Final volume = 95 mL

Final temperature = 310 K

Final pressure = ?

Solution:

Formula:

P₁V₁/T₁ = P₂V₂/T₂

P₂ = P₁V₁T₂ /T₁ V₂

P₂ = 110 KPa× 200 mL× 310 K /275 K  × 95 mL

P₂ = 6820000 KPa / 26125

P₂ = 261 KPa

The formation of bands in a crystal

Explanation:

- hope that helped :)

Answer:

Ar, P, Si, Mg, Na

Explanation:

Ar=106pm

P=107pm

Si=111pm

Mg=141pm

Na=166pm

Na>Mg>Si>P>Ar is the order of increasing atomic radius.

Elements are the simplest substances which cannot be broken down using chemical methods.

Atomic radii vary in a predictable way along or across the periodic table. The atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Thus we can say that helium is the smallest element, and francium is the largest.

Ar=106pm

P=107pm

Si=111pm

Mg=141pm

Na=166pm

Hence, Na>Mg>Si>P>Ar is the order of increasing atomic radius.

Learn more about elements here:

brainly.com/question/1896898

#SPJ2

Answer:

(The Formation Of Bands In A Crystal)

Answer:  

A: cold, cyclonic wind

B: deep ocean water

C: cold ocean water

E: warm ocean water

F: a strong cold front​

You only need A, B, C, E, F not D because that for tornadoes buddy.

Answer:

Tell picture above is a sample of tell me about yourself

Answer:

Number of neutrons in the nucleus.

Explanation:

Mass number is protons plus neutrons. Protons do not change from isotope to isotope

Answer:

seismographs

Explanation:

Scientists use seismographs that record the length and strength of each earthquake to try to determine if an eruption is imminent. Magma and gas can push the volcano's slope upward.

Answer:

the electron cloud model is the current model of atom

Answer:

a

Explanation:

covalent bonds are bonds between two nonmetals where they share an electron :)

Answer:

D

Explanation:

of water is 36.0 g. If any more NaCl is added past that point, it will not dissolve because the solution is saturated. If more solute is added and it does not dissolve, then the original solution was saturated. If the added solute dissolves, then the original solution was unsaturated.

Answer:

A product

B coefficient

C script

D rectant

Answer:

evaporation and distilation

Explanation:

Answer:

3) the north Pacific Ocean

Explanation:

Maritime polar air is defined officially as: Maritime polar (mP) air masses are cool, moist, and unstable. Some maritime polar air masses originate as continental polar air masses over Asia and move westward over the Pacific, collecting warmth and moisture from the ocean

Basically it's the North Pacific Ocean because of the higher latitude and colder air temperature

Answer:

936g/mol

Explanation:

To find the molar mass of a molecule, you find the sum of the molar masses of each atom in the molecule.

This compound has 40 carbon atoms, 60 Hydrogen atoms, 10 Nitrogen atoms, 12 Oxygen atoms, and 2 Sulphur atoms.

The molar mass of:

[tex](12 \times 40) + (60 \times 1) + (14 \times 10) + (16 \times 12) + (32 \times 2) = 936[/tex]