How do you measure density?

Density over mass
Mass over volume
Volume over density
Mass over density

Answer:

4.92L

Explanation:

Given parameters:

Initial pressure  = 891mmHg

Initial temperature  = 84°C  = 84 + 273  = 357k

Initial volume  = 5.61L

New temperature  = 40°C   = 273 + 40  = 313k

Unknown:

New volume  = ?

Solution:

Since we are dealing with constant pressure condition, we apply charles's law.

It states that the volume of a fixed mass of gas varies directly as its absolute temperature if the pressure is constant.

    Mathematically ;

         [tex]\frac{V1}{T1}[/tex]    = [tex]\frac{V2}{T2}[/tex]  

V1 is the initial volume                     V2 is the new volume

T1 is the initial temperature             T2 is the new temperature

   [tex]\frac{5.61}{357}[/tex]   = [tex]\frac{V2}{313}[/tex]  

           V2  = 4.92L

Answer:

The atomic number of silicon 14

According to periodic table

The atomic number of silicon is 14

Hope it helps:)

ANSWER:

moles CO2 = 88 mol

EXPLAIN:

In order to go from molecules of CO2 to moles of CO2, we have to use the following relationship:

I usually set up dimensional analysis questions like this:

Quantity sought = Quantity given x conversion factor

Now we just plug the values into the format I have above (make sure your units cancel out as you are going through this process, that's how you know if you are doing the calculations correctly or not):

moles CO2 = 5.3×10∧25 molecules×1mol/6.02×10∧23 molecules

moles CO2 = 88 mol

Answer:

A. Metalloids.

Explanation:

Metalloids. Metalloids, also called semiconductors, are the elements that border the zigzag line on the periodic table.

The Ni ( NO₃ )₃ is an anhydrous covalent compound.  Ni ( NO₃ )₃ is prepared by the reaction of red fuming nitric acid and nickel nitrate hemihydrate.

An electron exchange that results in the formation of electron pairs between atoms is known as a covalent bond. Bonding pairs or sharing pairs are the names given to these electron pairs. Covalent bonding is the stable equilibrium of the attractive and repulsive forces between atoms when they share electrons.

At room temperature, covalent compounds can be found in all three of their physical states and often have low boiling and melting temperatures. Because covalent compounds lack charged particles with the ability to carry electrons, they do not conduct electricity.

Two atoms sharing a pair of electrons make a covalent connection. Because the electron pair is drawn to both nuclei, the atoms are kept together.

Thus, The Ni ( NO₃ )₃ is an anhydrous covalent compound.

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Answer:

5.6[tex]\frac{6.02*10^{23} }{1}[/tex] = 3.4 X [tex]10^{24}[/tex]

Explanation:

the correct answer to it is 3.4 instead of 3.2. I got 3.4 from rounding it from 3.37.

The number of atoms in 5.6 moles of Na have been [tex]\rm \bold{3.37\;\times\;10^2^4}[/tex] atoms.

Atoms have been defined as the smallest unit of matter. The number of atoms in a mole of compound has been given by Avogadro law.

According to the Avogadro law, the number of atoms in mole of sample has been equal to the Avogadro number. The values of Avogadro number has been [tex]6.023\;\times\;10^2^3[/tex].

The available moles of Na have been 5.6 moles.

The number of atoms has been given by:

[tex]\rm 1\;mol=6.023\;\times\;10^2^3\;atoms\\ 5.6\;mol=5.6\;\times\;6.023\;\times\;10^2^3\;atoms\\ 5.6\;mol=3.37\;\times\;10^2^4\;atoms[/tex]

The number of atoms in 5.6 moles of Na have been [tex]\rm \bold{3.37\;\times\;10^2^4}[/tex] atoms.

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Answer:

B

Explanation:

Answer:

2 hydrogen and 1 oxygen

Explanation:

H2O

Hydrogen has the coefficient so you multiply 1 by 2 and it equals 2

Oxygen does not have any sub or coe so its automatically 1

Explanation:

The amount of rainfall would have the greatest impact on the amount of water available for people in this area. The more the rainfall the more water soaks through layers of porous rocks.Hence, level of water table will remain sufficient for easy pumping of water to the homes.Texas receives plenty of rainfall in a year.In a single year the region can receive up to 48 inches (1,200 mm) of precipitation, and flooding is common near rivers and in low-lying areas. Therefore water table remains intact throughout the year.

Answer:

It is soft and white. It has a low melting and boiling point, a good conductor electricity, and reacts with water. Furthermore, it is also highly reactive, malleable, and ductile.

Explanation:

Hope I helped!

Answer:

silvery-white and waxy

Explanation:

Properties means the observations you can make just by looking at it or the qualities that the object has.

So when I looked at the sodium I saw a silvery-white metal (sodium is a metal), that has this waxy appearance to it.

Answer:

Lithium

Explanation:

Answer:Conduction: Touching a stove and being burned. Ice cooling down your hand

Convection: Hot air rising, cooling, and falling (convection currents)

Radiation: Heat from the sun warming your face

Explanation:

Answer:

Radiation: Radio Waves, Conduction: An ice cube on a warm hand, Convection: A radiator

Answer: The United States

The United States is the only country to have successfully conducted crewed missions to the Moon, with the last departing the lunar surface in December 1972.

Explanation:

Answer

Only the United States has successfully landed men on the moon.

Explanation:

The United States is the only country to have successfully conducted crewed missions to the Moon, with the last departing the lunar surface in December 1972.

Answer:

its the last one

Answer:

D

Explanation:

Answer:

Cr2O3

Explanation:

To find the empirical formula, which is the smallest whole number ratio of a compound, the following is done:

68.4% Cr = 68.4g of Chromium

31.6% O = 31.6g of Oxygen

Since, Cr = 52, O = 16, divide each mass by their respective atomic mass to convert to moles.

Cr = 68.4/52 = 1.315 mol

O = 31.6/16 = 1.975 mol

- Next, we divide each mole value by the smallest value (1.315mol)

Cr = 1.315/1.315 = 1

O = 1.975/1.315 = 1.50

The ratio or Cr to O is 1:1.5

We multiply this ratio by 2 to get the whole number ratio as follows:

2 × 1: 2 × 1.5

2:3

Hence, the empirical formula of Cr and oxygen is Cr2O3.

Answer:

Only reaction 1

Explanation:

C + O2 → CO

the charge of C in CO is +2 (oxidation)

from 0 to +2

the charge of O in CO is -2 (reduction)

from 0 fo -2

Hence it is a redox (reduction-oxidation) reaction

This is also valid for,

C + O2 → CO2

the charge of C in CO2 is +4 (oxidation)

charge increases from 0 to +4

the charge of O in CO2 is -2 (reduction)

charge decreases from 0 to -2

hence, it is a redox reaction

K2SO4 + CaCl → KCl + CaSO4

none of the charges changes in this reaction

please recheck, for this may not be the correct answer

Answer:

723 torr

Explanation:

Using the formula;

P1V1/T1 = P2V2/T2

Where;

P1 = initial pressure (torr)

V1 = initial volume (Litres)

T1 = initial temperature (°C)

P2 = final pressure (torr)

V2 = final volume (L)

T2 = final temperature (°C)

Based on the information provided in this question, V1 = 4.40L, P1 = 555 torr, T1 = 33.0 °C + 273 = 306K, V2 = 3.50 L, P2 = ?, T2 = 44.0 °C + 273 = 317K.

Using the formula above:

555 × 4.4/306 = P2 × 3.5/317

2442/306 = 3.5P2/317

Cross multiply;

2442 × 317 = 306 × 3.5P2

774114 = 1071 P2

P2 = 774114 ÷ 1071

P2 = 722.79

P2 = 723 Torr

Answer:

0.0000101 grams.

Explanation:

First of all, use Avogadro's number to convert from molecules to moles.

Avogadro's number is 6.02 x 10^23.

Second of all, to convert from moles to grams, find the substance formula of phosphorus trichloride. After finding the substance formula, then find the molar mass of phosphorus trichloride.

Phosphorus trichloride is PCl3

Now find the molar mass of PCl3

P = 31.0 amu

Cl = 35.5 amu

They are three chlorine atoms and one phosphorus atom. So you do this.

31.0(1) + 35.5(3) = 137.5 g/mol

Now use dimensional analysis to show your work

4.6 x 10^16 grams of PCl3 * 1 mol/ 6.02 x 10^23 * 137.5 g/mol / 1 mol

The grams and the moles cancel out.

So now do [(4.6 x 10^16) / (6.02 x 10^23)] x 137.5

and you will get 0.000010507

4.6 has the fewest digits which is 2.

So use sig figs and the answer rounds to the nearest millionths.

0.000010507 rounds to 0.0000101

So the final answer is 0.0000101 grams(don't forget the units)

Hope it helped!

Answer:

As temperature increases, a substance will change from solid, to liquid, to gas. ... Apply Butter is made by intentionally changing the density of liquid milk.

Explanation:

5.2 mol H₂O

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Stoichiometry

Step 1: Define

[RxN - Balanced] 6HCl + Fe₂O₃ → 2FeCl₃ + 3H₂O

[Given] 10.4 mol HCl

Step 2: Identify Conversions

[RxN] 6 mol HCl = 3 mol H₂O

Step 3: Stoichiometry

Answer:

How to Draw a Lewis Structure.

Step 1: Find the Total Number of Valence Electrons.

Step 2: Find the Number of Electrons Needed to Make the Atoms "Happy".

Step 3: Determine the Number of Bonds in the Molecule.

Step 4: Choose a Central Atom.

Step 5: Draw a Skeletal Structure.

Step 6: Place Electrons Around Outside Atoms.

Explanation:

Hope this helped! :)

Answer:

3

Explanation:

It is based on empirical evidence

The characteristic of science is that it is based on empirical evidences comprising of a hypothesis.

Hypothesis can be defined as an assumption which is made for the sake of argument . It is an interpretation of a practical condition for which action needs to be taken.It is defined as a tentative assumption which is made to test logical consequences.It is an antecedent clause of a statement which is conditional.

It is constructed before research. There are six types of hypothesis 1)simple hypothesis 2) complex hypothesis 3) directional hypothesis 4)non-directional hypothesis 5) null hypothesis 6)casual hypothesis

The hypothesis should be clear and precise, it must be specific and way of explanation of hypothesis should be simple.

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Answer:

Weaker

Explanation:

Since the charges on nucleus and electron are opposite in nature, an attractive force exists between them. It is true in generally, that when objects are made to move closer together in the direction of an attractive force, potential energy decreases (and increases whenever attracting objects are force to move apart).

Here, we are required to determine if the attraction or repulsion grow weaker or stronger.

First, we must establish scenarios when there can be attraction and ones where there can be repulsion.

By the law guiding electric charges; In electrical interactions:

Like poles repel while Unlike poles attract.

Ultimately, when an electron gets closer to the nucleus, the attraction force will grow stronger due to the reduced distance between the electron and the nucleus.

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Answer:

Partial pressure of Ar = 0.73 atm

Explanation:

Given data:

Volume of flask = 1.00 L

Mass of Ar = 1.20 g

Temperature = 25 °C (25+273.15 K= 298.15 k)

Total pressure = 1.300 atm

Partial pressure of Ar = ?

Solution:

First of all we will calculate the number of moles of Ar:

Number of moles = mass/ molar mass

Number of moles = 1.20 g/ 39.95 g/mol

Number of moles = 0.03 mol

Pressure of Ar:

PV = nRT

R = general gas constant = 0.0821 atm.L /mol.K

P×1.00 L =  0.03 mol ×  0.0821 atm.L /mol.K× 298.15 k

P = 0.73 atm.L /1.00 L

P = 0.73 atm

Total pressure = Partial Pressure of Ar + Partial pressure of ethane

1.300 atm = 0.73 atm + P(ethane)

P(ethane) = 1.300 atm - 0.73 atm

P(ethane) = 0.57 atm

Answer:

Pb(OH)2 + 2 HCl ---> 2H2o + PbCl2

Explanation:

Answer:

1st chemical equation → Chemical change

2nd chemical equation → Physical change

3rd chemical equation → Physical change

4th chemical equation → Chemical change

Explanation:

Chemical change has to the do with the creation of an entirely new product or  substance. When two reactants react and form entirely new product(s), we say that a chemical change has occurred.

While a physical change does not create an entirely new substance or product; it can only change to a new form or state.

From the given equations, we discover that in the first equation, propane reacted with oxygen to give carbon (II) oxide and water (entirely new products) while in the second chemical equation, ethanol is a liquid (at room temperature) but later changes its state to gas (physical change).

The above answer is correct.  

Answer:

1.9g of F₂ were consumed in the reaction

Explanation:

Based on the chemical reaction:

2NaCl + F₂ →  2 NaF + Cl₂

Where 2 moles of NaCl react per mole of F₂ to produce 2 moles of NaF and 1 mole of Cl₂

To understand in a better way how the reaction occurs we need to convert each mass of compound to moles:

Moles of NaCl -Molar mass: 58.44g/mol-:

5.4g * (1mol / 58.44g) = 0.092 moles NaCl

Moles of NaF -Molar mass: 41.988g/mol-:

4.9g * (1mol / 41.998g) = 0.12 moles NaF

Moles of Cl₂ -Molar mass: 70.90g/mol-:

3.7g * (1mol / 70.90g) = 0.052 moles Cl₂

That means approximately 0.1 moles of NaCl react with 0.05 moles of F₂ to produce 0.1moles of NaF and 0.05 moles of Cl₂.

0.05 moles of F₂ are:

0.05 moles * (38g/mol) =