Is burning sugar a chemical or physical change? Please provide explanation

Answer:

a. KCl, c. BaCl2 and e. LiF.

Explanation:

Hello,

In this case, we can identify the ionic compounds by verifying the difference in the electronegativity between the bonding compounds when it is 1.7 or more (otherwise it is covalent) as shown below:

a. KCl: 3.0-0.9=2.1 -> Ionic.

b. C2H4: 2.5-2.1=0.4 -> Covalent.

c. BaCl2: 3.0-0.8=2.2 -> Ionic.

d. SiCl4: 3.0-1.8=1.2 -> Covalent.

e. LiF: 4.0-1.0=3.0 -> Ionic.

Therefore, ionic compounds are a. KCl, c. BaCl2 and e. LiF.

Regards.

Answer:

Approximately [tex]2.64\times 10^{20}[/tex] (assumption: wavelength [tex]525\; \rm nm[/tex] is measured in vacuum, where the speed of light is approximately [tex]3.0\times 10^{8}\; \rm m \cdot s^{-1}[/tex].)

Explanation:

Convert the unit of wavelength to meters:

[tex]\displaystyle \lambda = 525\; \rm nm = 525 \; \rm nm\times \frac{10^{-9}\; \rm m}{1\; \rm nm} = 5.25 \times 10^{-7}\; \rm m[/tex].

Assume that the wavelength [tex]525\; \rm nm[/tex] is measured in vacuum, where the speed of light is approximately [tex]2.99792\times 10^{8}\; \rm m \cdot s^{-1}[/tex]. Calculate the frequency of this light from its wavelength:

[tex]\displaystyle f = \frac{c}{\lambda} \approx \frac{2.99792\times 10^{8}\; \rm m \cdot s^{-1}}{5.25 \times 10^{-7}\; \rm m} \approx 5.71429\times 10^{14}\; \rm s^{-1}[/tex].

The Planck's Constant can help find the energy of a photon given its frequency. Look up this constant to more than three significant figures:

[tex]h \approx 6.62607\times 10^{-34}\; \rm J \cdot s^{-1}[/tex].

Calculate the energy of one such photon:

[tex]\begin{aligned} E &= h \cdot f\\ &\approx 6.62607\times 10^{-34}\; \rm J \cdot s^{-1} \times 5.71023\times 10^{14}\; \rm s \\ &\approx 3.78370\times 10^{-19}\; \rm J \end{aligned}[/tex].

Calculate the number of these photons that [tex]100\; \rm J[/tex] of energy can produce under the assumption of [tex]100\%[/tex] conversion:

[tex]\displaystyle \frac{100\; \rm J}{3.78370\times 10^{-19}\; \rm J} \approx 2.64\times 10^{20}[/tex].

(Rounded to three significant figures.)

Answer:

11

Explanation:

so that is 20\100× 55 that gives you 11

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Answer:

a. 0.154 moles = 2.78x10²³ ions

b. 2.18x10⁻⁴ moles = 6.56x10²⁰ ions

c. 1.77x10²² ions = 0.0147 moles

Explanation:

The multiplication of volume of solution in liters times molarity gives the moles of solute.

a. Moles MgCl₂:

88mL = 0.088L * (1.75mol / L) = 0.154 moles MgCl₂

Uaing Avogadro's number:

0.154mol  *(6.022x10²³ molecules / 1 mol) = 9.27x10²² molecules.

As 1 molecule of MgCl₂ contains 3 ions:

Ions = 2.78x10²³

b. Moles Al₂(SO₄)₃:

Aluminium sulfate has a molar mass of 324.15g/mol:

0.321L * (0.22g Al₂(SO₄)₃ / L) * (1mol / 324.15g) = 2.18x10⁻⁴ moles.

1 molecule contains 5 ions:

2.18x10⁻⁴ moles  *(6.022x10²³ molecules / 1 mol) * 5 = 6.56x10²⁰ ions.

c. 8.83x10²¹ formula units of CsNO₃ = Number of molecules. Ions are:

8.83x10²¹ * 2 = 1.77x10²² ions

And moles are:

8.83x10²¹ Formula units * (1mol /  6.022x10²³) = 0.0147 moles

a. The number of moles and number of ions should be 0.154 moles and 2.78x10²³ ions

b. The number of moles and number of ions should be 2.18x10⁻⁴ moles and 6.56x10²⁰ ions

c.  The number of moles and number of ions should be 1.77x10²² ions and  0.0147 moles

a. Moles MgCl₂:

Here,

88mL = 0.088L * (1.75mol / L) = 0.154 moles MgCl₂

Now here we used Avogadro's number:

So,

0.154mol  *(6.022x10²³ molecules / 1 mol) = 9.27x10²² molecules.

Since 1 molecule of MgCl₂ contains 3 ions:

So,

Ions = 2.78x10²³

b. Moles Al₂(SO₄)₃:

Since Aluminum sulfate has a molar mass of 324.15g/mol:

So,

0.321L * (0.22g Al₂(SO₄)₃ / L) * (1mol / 324.15g) = 2.18x10⁻⁴ moles.

Now

1 molecule contains 5 ions:

So,

2.18x10⁻⁴ moles  *(6.022x10²³ molecules / 1 mol) * 5 = 6.56x10²⁰ ions.

c. Since

8.83x10²¹ formula units of CsNO₃ = Number of molecules. Ions are:

So,

8.83x10²¹ * 2 = 1.77x10²² ions

And moles are:

8.83x10²¹ Formula units * (1mol /  6.022x10²³) = 0.0147 moles

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Answer:

Average weekly rate of mowing lawns = 13 lawns (Approx)

Explanation:

Given:

Total lawns mowed = 229

Total number of period = 18 week

Find:

Average weekly rate of mowing lawns

Computation:

Average weekly rate of mowing lawns = Total lawns mowed / Total number of period

Average weekly rate of mowing lawns = 229 / 18

Average weekly rate of mowing lawns = 12.72

Average weekly rate of mowing lawns = 13 lawns (Approx)

Answer:

CaCO3,which is Calcium Carbonate. It’s equivalent mass is 50 g. Explanation:-. Mass of CaCO3=Mass of 1 atom of Calcium (Ca)+Mass of 1 atom of Carbon (C)+Mass of 3 atoms of Oxygen (O). Mass of 1 atom of Calcium=1×40g=40g. Mass of 1 atom of Carbon=1×12g=12g. Mass of 3 atoms of Oxygen=3×16g=48g.

Explanation:  Hope this helps :)

Answer:

heterogeneous

Explanation:

Answer:

-2m/s/s

Explanation:

Acceleration = change in speed / change in time

Change in speed = final speed - initial speed

In this case the change in speed was 10m/s - 30m/s = -20m/s

And change in time was 10 sec (within 10 sec)

Therefore acceleration = -20/10 = -2m/s/s

The acceleration is negative because the car slowed down (decelerated essentially) and the unit for acceleration is meters per second per second because it is the change in speed per second.

Hope this helped!

Answer:

Explanation:

A mole is the amount of substance that contains as many elementary entities as there are carbon atoms in 12 grams of carbon -12 isotopes i.e. it is the amount of a substance that posses the same number of particles as the number of atoms in exactly 12g of carbon is 12.

The number of atoms in a mole is known to be the Avogadro Number which is equal to 6.02 × 10²³. Thus, a mole of any substance is that amount of the substance which contains 6.02 × 10²³ particles of that substance. The definition of the mole is also given by the relationship:

[tex]\mathtt {moles = \dfrac{ mass \ in \ grams}{ relative \ molecular \ mass}}[/tex]

Answer:

Explanation:

An amino acid like lysine has both the acidic and basic group . They are amphoteric in nature ie they can react with both acid and base . In acidic or basic medium they carry charge of either positive or negative nature .

Lysine is also an amino acid . It has both acidic and basic group . The pka value of its basic side chain is 10.5 . Hence at pH more than it it is neutral or have no charge but at pH value less than 10.5 , it acquires H⁺ ion and becomes positively charged

Hence at pH value of 9.5 which is less than 10.5 , it will be positively charged . It will have net charge of + 1 .

----    NH₂  + H⁺ =     ------ NH₃⁺

Answer:

yes it can

Explanation:

a model can be improved so much that it increases your chances of (insert what ever you are writing about) and then describe why:)

Answer:

the number of Protons equals the number of Electrons.

Explanation:

Edg 2021

In an electrically neutral atom, the number of protons equals the number of electrons. Thus, the correct option for this question is B.

Protons may be defined as the type of sub-atomic particles that are present in the nucleus of an atom along with neutrons. These sub-atomic particles are positively charged in nature. Protons are thought to be discovered by Ernest Rutherford.

Electrons are also the type of sub-atomic particles which are continuously revolving around the nucleus of an atom. These sub-atomic particles are negatively charged in nature.

So, when the number of protons is more as compared to the number of electrons, an atom possesses a positive charge while the number of protons is found to be less compared to the number of electrons, and an atom possesses a negative charge.

Therefore, in an electrically neutral atom, the number of protons equals the number of electrons. Thus, the correct option for this question is B.

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Answer:

0.25 M

Explanation:

Data obtained from the question include:

Molar mass of NaCl = 58.55 g/mol

Mass of NaCl = 0.800 g

Volume = 54.6 mL

Next, we shall determine the number of mole in 0.800 g of NaCl. This can be obtained as follow:

Molar mass of NaCl = 58.55 g/mol

Mass of NaCl = 0.800 g

Mole of NaCl =?

Mole = mass /Molar mass

Mole of NaCl = 0.8/58.55

Mole of NaCl = 0.0137 mole

Next, we shall convert 54.6 mL to litres (L). This can be obtained as follow:

1000 mL = 1 L

Therefore,

54.6 mL = 54.6 /1000

54.6 mL = 0.0546 L

Finally, we shall determine the molarity of the solution as follow:

Mole of NaCl = 0.0137 mole

Volume = 0.0546 L

Molarity =?

Mol= mole /Volume

Molarity = 0.0137/0.0546

Molarity = 0.25M

Therefore, the molarity of the solution is 0.25 M

Answer:

The last digit in any measured quantity of a tool is the minimum it can measure so

5 books ---- Exact number

5 lb ---- measured

9.23 g----- measured

9.035Kg measured

12 roses ------ exact

12 inches in 1 foot ----- exact

361 miles ------- measured

100 cm in 1 m ------- exact

Answer:

Tetrasulfur Dinitride   S4N2

Tetrasulfur pentoxide   S4N4

Tetrasulfur tetranitride  N4S4

Tetrasulfur pentoxide   S4N4

Answer : The correct IUPAC name for the compound is, 2,2,4,5-tetramethyl-3-ethylhexane.

Explanation :

The basic rules for naming of hydrocarbons are :

First select the longest possible carbon chain.

The longest possible carbon chain should include the carbons of double or triple bonds.

The naming of alkane is done by adding the suffix -ane, alkene by adding the suffix -ene, alkyne by adding the suffix -yne.

If two or more similar alkyl groups are present in a compound, the prefixes di-, tri-, tetra- and so on are used to specify the number of times of the alkyl groups in the chain.

In the give compound, the longest possible carbon chain has 6 carbon atoms. So, the prefix used will be 'hex-' and also the carbon has single bond between them, so it is an alkane. Four methyl group is present at 2,2,4,5 position of carbon chain and one ethyl group is present at 3 position.

Hence, the correct IUPAC name for the compound is, 2,2,4,5-tetramethyl-3-ethylhexane.

Tetramethyl-2,2,4,5-ethylhexane is the proper IUPAC name for the substance.

Basic guidelines for hydrocarbon naming are as follows:

Choose the longest carbon chain you can.

The carbons of double or triple bonds should be included in the longest carbon chain possible.

The suffixes -ane, -ene, and -yne are used in the naming of alkane, alkene, and alkyne, respectively.

If a compound has two or more identical alkyl groups, the prefixes di-, tri-, tetra-, and so on are used to indicate how many times the alkyl groups are present in the chain.

The longest feasible carbon chain in the given chemical contains 6 carbon atoms. Since there is only one bond between the carbon atoms, the prefix will be "hex-," and an alkane is what is being described. On the carbon chain, there are four methyl groups at positions 2, 2, 4, and 5, and one ethyl group at position 3. Consequently, 2,2,4,5-tetramethyl-3-ethylhexane is the right IUPAC designation for the substance.

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Answer:

To speed up a reaction

Explanation:

Heat, as well as catalysts, increase the reaction rate of some chemical reactions since they cause the enzymes or reagents in charge of carrying out the transformation to products to act faster and increase their kinetic energy of reaction.

Answer:

Explanation:

wt. of the lead = wt. of ( flask + lead) - wt.of the empty flask

                      350.52- 245.61= 104.91 grams of lead

density = mass/volume

11.43= 104.91/V

V =  9.178 ml

Answer:

The liquid state has a definite volume and a definite shape.

Answer:

A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable. This increases the reliability of the results, often through a comparison between control measurements and the other measurements.A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable. This increases the reliability of the results, often through a comparison between control measurements and the other measurements.

Explanation:

Let's all give it up for GOOGLE! where you can literally get an answer to something.

Answer:

474 grams of chlorine gas are present in a 150 liter cylinder of chlorine held at a pressure of 1.00 atm and 0 °C

Explanation:

An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:  

P*V = n*R*T

where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas.

In this case:

Replacing:

1.00 atm* 150 L= n*0.08206 [tex]\frac{atm*L}{mol*K}[/tex] *273 K

Solving:

[tex]n=\frac{1.00 atm* 150 L}{0.08206 \frac{atm*L}{mol*K}*273 K}[/tex]

n= 6.69 moles

Being Cl= 35.45 g/mole, the molar mass of chlorine gas is:

Cl₂=2*35.45 g/mole= 70.9 g/mole

So if 1 mole has 70.9 grams, 6.69 moles of the gas, how much mass does it have?

[tex]mass=\frac{6.69 moles*70.9 grams}{1 mole}[/tex]

mass= 474.321 grams ≅ 474 grams

474 grams of chlorine gas are present in a 150 liter cylinder of chlorine held at a pressure of 1.00 atm and 0 °C

D. Make observations

The first thing you do is write a hypothesis then you were designed your procedure, after you make the procedure you would do the procedure, after you do the procedure you would confirm the results, then at the end you would make observations to see that everything is correct.

Answer:

4.

Explanation:

Hello,

In this case, for the calculation of the degree of unsaturation, we apply the following formula:

[tex]Degree\ of \ insaturation=C-\frac{H}{2}[/tex]

Thus, since we have eight carbon atoms and twelve hydrogen atoms, it turns out:

[tex]Degree\ of \ insaturation=8-\frac{12}{2}=8-6=4[/tex]

It means that four substituents are missing in order saturate the molecule.

Regards.

Answer:

Explanation:

Start by sifting the marbles out bc they are bigger they will sit in a big sifter

Than with a magnet roll it in what’s left this will pick up all the iron pieces

Than Fill with water and stir this should resolve the sugar which after you sift out the sand you can heat and scrape off beaker and than for a very short time heat up the sand to dry it and not have extra weight from the water

!!!sand only for a few seconds or else it will fly everywhere and if it gets in eye it will sting badly

Answer:

Explanation:

The density of a substance can be found by using the formula

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

To find the density in g/mL , we must first convert the volume from L to mL

From the question

mass = 440 g

1 L = 1000 mL

0.27 L = 0.27 × 1000 = 270 mL

volume = 270 mL

Substitute the values into the above formula and solve for the Density

That's

[tex]Density = \frac{440}{270} [/tex]

= 1.629629...

We have the final answer as

Hope this helps you

Answer:

The answer to your question is given below.

Explanation:

The following data were obtained from the question:

Speed limit = 60 km/h

To know if the car was speeding, let us calculate the speed of the car.

This can be obtained as follow:

Distance (d) = 5 m

Convert 5 m to km

Recall:

1000 m = 1 km

5 m = 5/1000

5 m = 0.005 km

Time (t) = 0.2 sec.

Convert 0.2 sec to hour.

Recall:

3600 secs = 1 h

Therefore,

0.2 sec = 0.2/3600

0.2 sec = 5.56×10¯⁵ h

Thus,

Distance (d) = 0.005 km

Time (t) = 5.56×10¯⁵ h

Speed of car =?

Speed = Distance /time

Speed = 0.005/5.56×10¯⁵

Speed of the car = 90 km/h

Comparing the speed of the car (i.e 90 km/h) to the speed limit of the zone (i.e 60 km/h), we can see that the car is on a high speed since its speed (i.e 90 km/h) is higher than the speed limit of the zone (i.e 60 km/h).

Speed of the car = 90 km/h

Speed limit = 60 km/h

Difference = 90 – 60

Difference = 30 km/h

Therefore, the car is speeding by 30 km/h more compared to the speed limit.

Answer:

11,000 cm

Explanation:

Step 1: Given data

Width of the field (w): 17 meters

Length of the field (l): 38 meters

Step 2: Calculate the perimeter of the field

The field is a rectangle. We can find its perimeter (P) by adding its sides.

P = 2 × w + 2 × l = 2 × 17 m + 2 × 38 m = 110 m

Step 3: Convert the perimeter to centimeters

We will use the relationship 1 m = 100 cm.

110 m × (100 cm/1 m) = 11,000 cm