how many moles of sodium are present in a sample of sodium having a mass of 137 g? (molar mass is 23.0g)

Answer:

Examples of measured numbers: The diameter of a coin, such as 10.2 mm. The weight of an object, such as 8.887 grams. The length of a pen, such as 12 cm.

Explanation:

Answer:

It completely depends on what you are measuring, what instrument you are using, and the uncertainty associated with your measurement.

Explanation:

When expressing a measurement, there is always going to be a part that you know, and a part that you guess. They both make up known numbers collectively called significant figures (commonly shortened to "sig figs"). For instance, imagine you are measuring the length of a pencil. Let's say it is a typical ruler with divisions of 0.1 cm (picture for reference). You measure the pencil, and to your eyes it looks like it is about 9 cm and 5 small tick marks (so, 0.5 cm), so we'll call that 9.5 cm. Now, this is a known value, so you are certain that it is a least 9.5 cm. However, it may be true that there is one more decimal place that can be known. The general rule is that you want to add one more uncertain digit to the rightmost side of the number, and how many digits depends on the divisions of the instrument. Our ruler has divisions of 0.1 cm (the small tick marks), and so we will go one more place out, and add another digit. Now, let's say our eyes are pretty good, so let's say it's 9.5 cm, and then add that one uncertain digit, a 0 to the smallest division of 0.1, so, 0.10. The final measurement we record is 9.50 cm. Now, it may seem like we are simply guessing or even being unreasonable in our assessment of how long this pencil is. I can promise you that not knowing the actual measurement of this pencil will not make a spaceship crash because of a specification that was not the "right measurement". For those life-or-death measurements, much more precise measurement machines are used; this is just a pencil. Also, it would be unreasonable to say that it is 9.500000 cm or 9.500001 cm. We do not have that kind of certainty with this ruler, only divisions of 0.1 cm, so we can only estimate out to one more decimal place.

In short, find the smallest division of a ruler or whatever device (like a chemical beaker) you are using, and then add one uncertain digit to the end of that. If it's 0.1 cm, then add one digit to that. (example: 5.6 --> 5.63; 3 because that is what it looks like on the ruler). If it's 1 cm, then add an extra .1, so the measurement is 1.1 cm. And of course, it's not always cm you are using, that was just an example. Best of luck!

Answer:

bond

Explanation:

It is a polar bond because it is when two atoms bond

Answer:

(1) Releases Energy

Explanation:

In the process called cellular respiration, energy is released from oxygen molecules.

Hope this helps!  \ (•◡•) /

Answer:

Alpha

Explanation:

^4 _2 He = alpha

^0 _-1 b = beta

^0 _0 y = gamma

Answer:  [tex]6.047\times 10^{23}[/tex] atoms in 1.004 mol of arsenic

Explanation:

According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.

To calculate the atoms, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given atoms}}{\text {avogadro's number}}[/tex]

[tex]1.004=\frac{x}{6.023\times 10^{23}}[/tex]

[tex]x=1.004\times 6.023\times 10^{23}=6.047\times 10^{23}[/tex]

Thus there are [tex]6.047\times 10^{23}[/tex] atoms in 1.004 mol of arsenic

Answer:

The Soufriere Hills volcano has formed where magma is actively seeping up from the mantle to the surface. Soufriere Hills volcano is part of an island chain that formed at the boundary where two oceanic plates converge. One plate subducts beneath the plate with the island chain, and the subducting plate melts in the mantle and creates magma that rises and fuels the Soufriere Hills volcano.

Explanation:

Answer:

2

Explanation:

Answer:

The postulate that all pure samples of a particular chemical compound contain the same elements  combined in the same proportion by mass.

Explanation:

The law of constant composition (or definite proportion) states that all pure samples of a particular chemical compound contain the same elements  combined in the same proportion by mass.

This law implies that irrespective of the source of the sample of the compound or the method by which the sample was prepared, as long as the sample is pure, the elements present in the compound are always combined in a specific ratio by mass. For example, water has the molecular formula H₂O. Irrespective of the water source, for example, tap-water, lake, stream, river or rainfall, each pure sample of water will have the constant composition of 2 atoms of hydrogen to one atom of oxygen.

The given compound exists as XO in nature. Therefore, irrespective of the source or method of preparation, every sample of this compound should have the formula XO. Since the compound prepared by the scientist was XO₂, therefore, the postulate that all pure samples of a particular chemical compound contain the same elements  combined in the same proportion by mass was violated by the scientist. The scientist must have prepared a different compound of the elemental compositions.

Answer:

Wood burning would be a chemical change

Explanation:

You cannot undo the change, since the burn will be permanent.

(Hope this helps! If it does not try specifying)

Answer:

B

Explanation:

scientists always look for evidence

Answer:

Yea its B

Explanation: The person above me legit toke the answer out of my mouth

Answer:

2.8g/cm³

Explanation:

Given parameters:

Mass of cube = 42g

Volume of cube  = 15cm³

Unknown:

Density of the cube  = ?

Solution:

Density is defined as the mass per unit volume of a substance. It is mathematically expressed as:

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

So;

 Density  = [tex]\frac{42}{15}[/tex]   = 2.8g/cm³

Answer:

Calcination refers to heating a solid to high temperatures in absence of air or oxygen, generally for the purpose of removing impurities or volatile substances.

Explanation:

hope it helps

Answer:

Thermohaline Circulation

Explanation:

The process is known as “Thermohaline Circulation”. In the Earth’s polar regions ocean water gets very cold, forming sea ice. As a consequence the surrounding seawater gets saltier, because when sea ice forms, the salt is left behind. As the seawater gets saltier, its density increases, and it starts to sink.

Answer:

The mass of oxygen needed to be pumped in the aquarium is 10 g

Explanation:

Here the value of the degree of solubility of oxygen in water is sought

The solubility of oxygen in fresh water is approximately 1.22 × 10⁻³ mol·dm⁻³ which is equivalent to approximately 40 mg/L

The volume of water the aquarium holds = 250 L

The mass of oxygen required = The solubility of oxygen in water × (The volume of water in the aquarium)

Therefore, the mass of oxygen needed to be pumped in the aquarium = 40 mg/L × 250 L = 10,000 mg

1,000 mg = 1 g

∴ 10,000 mg = 10 g

The mass of oxygen needed to be pumped in the aquarium = 10,000 mg = 10 g.

Answer:

recyclability

Explanation:

recyclability

Explanation:

hope this helps

Answer:

A. Silicon

Explanation:

The ability of an atom to attract electrons is known as electronegativity.

Electronegativity  is the measure of the relative tendency with which the atoms of the element attract valence electrons in a chemical bond.

Answer:

90.1km/hr

Explanation:

Given parameters:

Distance  = 30km

Time  = 20s  = 0.33hr

Unknown :

Speed of the car  = ?

Solution:

To solve this problem;

     Speed  = [tex]\frac{distance }{time}[/tex]  

Now insert the parameters and solve;

 Speed  = [tex]\frac{30}{0.333}[/tex]   = 90.1km/hr

Answer:

A)16.3% (Hexane's formula is C6H14)

Answer:

I think it's Nuclear

Answer:

C. 17

Explanation:

The question above is related to the "Periodic Table of Elements." The Halogen group is located on the right side of the table. It consists of six elements: Fluorine, Chlorine, Bromine, Iodine, Astatine and Tennessine.

The "atomic number" of an element refers to the number of protons that can be found in the element's nucleus. Among the halogens, "Chlorine" is the only one with an atomic number of 17. Halogens do not have an atomic number of 10, 136 and 13.

Aluminum is solid at room temperature and will, therefore, have a melting point that is above room temperature.

The room temperature is about 25 degrees Celsius.

Argon and oxygen are gases at room temperature.

Mercury is a liquid at room temperature.

Aluminum, on the other hand, is solid at room temperature. Hence, its melting point is definitely somewhere above room temperature.

More on melting points can be found here: https://brainly.com/question/25777663

Answer:

Strong acids contain more A− than weak acids do.

Strong acids contain more H3O+ than weak acids do

Explanation:

When we talk about a strong acid, we are referring to any acid that is completely dissociated or ionized when it is in an aqueous solution.

It is very eager to lose a proton, H+ in solution according Arrhenius definition.

In aqueous solution, a strong acid ionizes as follows:

HA(aq) + H2O → H3O+(aq) + A−(aq)

Since, strong acids ionize completely in solution, strong acids contain a greater H3O+ and A− concentration than solutions of weak acids.

Answer:

A. Strong acids contain more A− than weak acids do.

B. Strong acids contain more H3O+ than weak acids do.

D. Strong acids contain more OH− than weak acids do.

Explanation:

Plato correct

The unknown chemical : Nitrogen gas : N₂

Given

1 mole of the unknown chemical

mass = 28 g

Required

The unknown chemical

Solution

A mole is a number of particles(atoms, molecules, ions)  in a substance

This refers to the atomic total of the 12 gr C-12  which is equal to 6.02.10²³, so 1 mole = 6.02.10²³ particles  

Can be formulated :

mol = mass : molecular weight

Molecular weight(MW) = mass : mol

MW=28 g : 1 mol

MW= 28 g/mol

Because this compound is diatomic, it consists of 2 elements of the same type, so this element has a mass number:

28: 2 = 14

The element having the mass number 14 is N

Answer:

NEWTONS,  

Explanation:

Answer:

kilogram meters2/seconds2

joules

kilojoules

Explanation:

Answer: thay can't make cells

Explanation:

Answer:

How many molecules of water are there in 54 g of H2O H 2 O ? Solution. Molar Mass of H2O H 2 O = 2 + 16 = 18 g/moles. So ,number of moles of H2O H 2 O = Mass/Molar Mass = 54/18 =3 moles. Now 1 moles = 6.022×1023 6.022 × 10 23 molecule.

Answer:

Hibhibihbhubhibhbuhbuhbhub

Explanation:

Answer:

220g

Explanation:

The reaction equation is given as:

   2C₂H₆   +   7O₂  →  4CO₂   +   6H₂O

Number of moles of ethane gas = 2.5moles

To find the mass of CO₂ produced, we need to know the number of moles of the compound produced;

        2 mole of ethane gas produced 4 moles of CO₂

      2.5 moles of ethane gas will produce [tex]\frac{2.5 x 4}{2}[/tex]   = 5mole of CO₂  

So;

   Mass of CO₂   = number of moles x molar mass

    Molar mass of CO₂   = 12 + 2(16) = 44g/mol

 Mass of CO₂ = 5 x 44  = 220g

Answer:

Molar mass = 27 g/mol

Explanation:

Given data;

Number of moles of Al = 0.2 mol

Mass of Al = 5.4 g

Molar mass of Al = ?

Solution:

Formula:

Number of moles = mass/molar mass

By putting values,

0.2 mol = 5.4 g/ molar mass

Molar mass = 5.4 g/ 0.2 mol

Molar mass = 27 g/mol

Answer: the health isle next to tooth brushes maybe in a store? Why? Or in a closet? Umm

Explanation:

Answer:

The store.....is this like a trick question...? but yeah A store :))

Explanation: