When you test starch with Barfoed’s reagent, what would be the answer, positive or negative?

Answers

Answer 1

Answer:

It would test positive.


Related Questions

A solution is prepared by mixing 50.00 mL of 0.100 M HNO3 and 100.00 ml of 0.200 M Ca(NO3)2. Calculate the molarity of the nitrate ion in the final solution.

Answers

its 0.100 M HNO3 formula

A solution is prepared by mixing 50.00 mL of 0.100 M HNO3 and 100.00 ml of 0.200 M Ca(NO3)2. The molarity of the nitrate ion in the final solution is 0.1667 M.

What is molarity ?

The amount of a substance in a specific volume of solution is known as its molarity (M). The number of moles of a solute per liter of a solution is known as molarity. The molar concentration of a solution is another name for molarity.

Molarity (M), which is determined by dividing the solute's mass in moles by the volume of the solution in liters, is the most widely used unit to express solution concentration: liters of solution/moles of solute equals M. One liter of a solution with a 1.00 molar concentration (1.00 M) contains 1.00 moles of solute.

50.0 mL x 0.100 M

= 5.00 millimoles of HNO3

=0.00500 moles

100.0 mL x 0.200 M

= 20.0 millimoles of HNO3

=0.0200 moles

The whole solution has a volume of 150.0 mL

= 50.0+100.0

= 150

The whole solution contains 25.0 millimoles of HNO3

= 5.00+20.0

= 25

millimoles / mL = Molarity

25.0 / 150.0

= 0.1667 M

moles / Liters = Molarity

0.0250 / 0.1500

= 0.1667 M

Thus, The molarity of the nitrate ion in the final solution is 0.1667 M.

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If a solution has a concentration of 3.2x10-3 [OH-] what is the pOH of the solution?​

Answers

Answer:

The solution with [OH-] = 3.2x10-3 M will have an [H+] of 3.09x10–12 M.Explanation:

I dont understand this

Answers

Answer:

me too

Explanation:

The last one Metallic bonding

What happens to the speed of motion of the particles of a gas when a certain volume of the gas is heated at constant pressure? Explain your answer.

Answers

Answer:

The particles begin to move faster as the gas is heated. Since the gas remains at a constant pressure and volume, the particles are not able to spread out, so they move around the container even faster.

Explanation:

its just what happens

When a. certain volume of gas is heated at constant pressure, the speed of motion of the gas increases with temperature increase.

Amontons’s law.

Anontons law states that If the temperature is increased, the average speed and kinetic energy of the gas molecules increase. If the volume is held constant, the increased speed of the gas molecules results in more frequent and more forceful collisions with the walls of the container, therefore increasing the pressure.

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decay mode for cesium-137

Answers

Answer:

Beta decay

Explanation:

Radioactive decay changes one nucleus to another. The type of decay that a particular nucleus undergoes depends on the number of neutrons and protons present in such nucleus.

Radioactive decay tends to lead to the attainment of a stable neutron/proton ratio.

The decay mode for cesium-137 is beta decay. The beta decay of cesium-137 yields Barium-137.

Beta decay decreases the neutron - proton ratio.

C. Balance these fossil-fuel combustion reactions. (1 point)

Answers

The question is incomplete. The complete question is :

C. Balance these fossil-fuel combustion reactions. (1 point)

C8H18(g) + 12.5O2(g) →    ____CO2(g) + 9H2O(g) + heat

CH4(g) + ____O2(g) →     ____CO2(g) + ____H2O(g) + heat

C3H8(g) + ____O2(g) →    ____CO2(g) + ____H2O(g) + heat

C6H6(g) + ____O2(g)  →   ____CO2(g) + ____H2O(g) + heat

Solution :

C8H18(g) + 12.5O2(g) →    __8__CO2(g) + 9H2O(g) + heat

When 1 part of octane reacts with 12.5 parts of oxygen, it gives 8 parts of carbon dioxide and 9 parts of water along with liberation of energy.

CH4(g) + __2__O2(g) →     __1__CO2(g) + __2__H2O(g) + heat

When 1 part of methane reacts with 2 parts of oxygen, it gives 1 part of carbon dioxide and 2 parts of water along with liberation of energy.

C3H8(g) + __5__O2(g) →    __3__CO2(g) + __4__H2O(g) + heat

When 1 part of propane reacts with 5 parts of oxygen, it gives 3 part of carbon dioxide and 4 parts of water along with liberation of energy.

C6H6(g) + __1/2__O2(g)  →   __6__CO2(g) + __3__H2O(g) + heat

When 1 part of propane reacts with 1/2 parts of oxygen, it gives 6 part of carbon dioxide and 3 parts of water along with liberation of energy.

ok so i need a reasoning on What evidence have you discovered to explain how the curve of Earth’s surface affects temperatures on Earth?

Answers

The equator gets the most sun and has the warmest climate. This has to do with the tilt of the Earth on it’s axis. As you go north or south from the equator toward the poles the Earth’s temperature gets colder. It is harder for the sun’s direct rays & the curvature of the Earth to reach these points This has to do with the direct sunlight that reaches the equator. Think of a ball, or take a flashlight & shine it on a ball to see this yourself from different angles. The angle of the sun on the the Earth also causes different seasons.

how many moles of Carbon are in 3.06 g of Carbon

Answers

Answer:

[tex]\boxed {\boxed {\sf 0.255 \ mol \ C }}[/tex]

Explanation:

If we want to convert from grams to moles, the molar mass is used. This is the mass of 1 mole. They are found on the Periodic Table as the atomic masses, but the units are grams per mole (g/mol) instead of atomic mass units (amu).

Look up the molar mass of carbon.

Carbon (C): 12.011 g/mol

Set up a ratio using the molar mass.

[tex]\frac {12.011 \ g \ C}{ 1 \ mol \ C}[/tex]

Since we are converting 3.06 grams to moles, we multiply by that value.

[tex]3.06 \ g \ C*\frac {12.011 \ g \ C}{ 1 \ mol \ C}[/tex]

Flip the ratio. This way, the ratio is still equivalent, but the units of grams of carbon cancel.

[tex]3.06 \ g \ C* \frac{1 \ mol \ C}{12.011 \ g\ C}[/tex]                      

[tex]3.06 * \frac{1 \ mol \ C}{12.011 }[/tex]    

[tex]\frac {3.06}{12.011 } \ mol \ C[/tex]                                

[tex]0.25476646 \ mol \ C[/tex]

The original measurement of grams (3.06) has 3 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place.

0.25476646

The 7 in the ten-thousandth place tells us to round the 4 up to a 5.

[tex]0.255 \ mol \ C[/tex]

3.06 grams of carbon is approximately 0.255 moles of carbon.

Under the right conditions aluminum will react with chlorine to produce aluminum chloride.
2 Al + 3 Cl2 - 2 AlCl3
How many grams of aluminum are needed to react completely with 11.727 liters of chlorine?

Answers

Answer:

[tex]m_{Al}=9.42gAl[/tex]

Explanation:

Hello there!

In this case, according to the given chemical reaction:

2 Al + 3 Cl2 --> 2 AlCl3

Whereas there is a 2:3 mole ratio of aluminum to chlorine; it will be possible for us to calculate the required grams of aluminum by using the equality 22.4 L = 1 mol, the aforementioned mole ratio and the atomic mass of aluminum (27.0 g/mol) to obtain:

[tex]m_{Al}=11.727LCl_2*\frac{1molCl_2}{22.4LCl_2}*\frac{2molAl}{3molCl_2} *\frac{27.0gAl}{1molAl} \\\\m_{Al}=9.42gAl[/tex]

Regards!

does the nitro group on the pyridine ring make the ring more electron rich or more electron deficient

Answers

Answer:

more electron deficient

Explanation:

The nitro group is an electron withdrawing group. It withdraws electrons from the pyridine ring by resonance.

This electron withdrawal by resonance makes the pyridine ring less electron rich or more electron deficient.

Hence, the nitro group makes the pyrinde ring more electron deficient

Given the reaction: N2 + O2 = 2NO for which the Keq at 2273 K is 1.2 x 10-4
a. Write the equilibrium constant expression for the reaction.
b. Write the equation that would allow you solve for the concentration of NO.
c. What is the concentration of NO if [NZ] = 0.166M and [02] = 0.145M?

Answers

Answer:

(a): The expression of equilibrium constant is [tex]K_{eq}=\frac{[NO]^2}{[N_2][O_2]}[/tex]

(b): The equation to solve the concentration of NO is [tex][NO]=\sqrt{K_{eq}\times [N_2]\times [O_2]}[/tex]

(c): The concentration of NO is 0.0017 M.

Explanation:

The equilibrium constant is defined as the ratio of the concentration of products to the concentration of reactants raised to the power of the stoichiometric coefficient of each. It is represented by the term [tex]K_{eq}[/tex]

(a):

The given chemical equation follows:

[tex]N_2+O_2\rightarrow 2NO[/tex]

The expression for equilbrium constant will be:

[tex]K_{eq}=\frac{[NO]^2}{[N_2][O_2]}[/tex]

(b):

The equation to solve the concentration of NO follows:

[tex][NO]=\sqrt{K_{eq}\times [N_2]\times [O_2]}[/tex]            ......(1)

(c):

Given values:

[tex]K_{eq}=1.2\times 10^{-4}[/tex]

[tex][N_2]_{eq}=0.166M[/tex]

[tex][O_2]_{eq}=0.145M[/tex]

Plugging values in equation 1, we get:

[tex][NO]=\sqrt{(1.2\times 10^{-4})\times 0.166\times 0.145}[/tex]

[tex][NO]=\sqrt{2.88\times 10^{-6}}[/tex]

[tex][NO]=0.0017 M[/tex]

Hence, the concentration of NO is 0.0017 M.

Calculate the percent composition by mass of iron in Fe(NO3)3

Answers

Answer:

It's 23.14 percent

Explanation:

First, the mass of all the elements are:

N = 14

O = 16

Fe = 56

In this molecule you have 3 atoms of N, and 9 atoms of O, so:

3•14 = 42

16•9 = 144

The whole mass of the molecule is:

56 + 42 + 144 = 242

242/100 = 2.42, so 1% is 2.42

56/2.42 = 23.14%

how will you know whether the crystallization point is reached​

Answers

Answer:

Place a glass rod in the solution, if the crystallisation point has been reached, you should notice small crystals formed on it.

BRAINISEST & 10 POINTS

Answers

Answer:

In order from left to right, 7 (gamma), 5 (ultraviolet, now continue pattern), 4, 6, 2, 3, 1.

Consider the equation A(aq) 2B(aq) 3C(aq) 2D(aq). In one experiment, 45.0 mL of 0.050 M A is mixed with 25.0 mL 0.100 M B. At equilibrium the concentration of C is 0.0410 M. Calculate K. g

Answers

Answer:

K = 0.0396

Explanation:

Based on the reaction:

A + 2B ⇄ 3C + 2D

Where equilibrium constant, K, is:

K = [C]³[D]² / [A] [B]²

The initial concentrations of A and B are:

[A]₀ = 0.050M * (45.0mL / 70.0mL) = 0.0321M

[B]₀ = 0.100M * (25.0mL / 70.0mL) = 0.0357M

As [C] = 0.0410M, the molar concentration of D is:

0.0410M * (2mol D / 3mol C) = 0.0273M = [D]

And the concentration of A and B that reacted was:

0.0410M * (2mol B / 3mol C) = 0.0273M B

0.0410M * (1mol A / 3mol C) = 0.0137M A

Equilibrium concentration B and A:

0.0357M - 0.0273M = 0.0084M = [B]

0.0321M - 0.0137M = 0.0184M = [A]

And K is:

K = [0.0410M]³[0.0273M]² / [0.0184M] [0.0084M]²

K = 0.0396

If the volume of water in a cylinder is 8.0mL, but changes to 10.0mL when a solid is carefully lowered into it, the volume of the solid is?

Answers

Answer:

2 mL.

Explanation:

From the question given above, the following data were obtained:

Volume of water = 8 mL

Volume of water + solid = 10 mL

Volume of solid =?

The volume of the solid can be obtained as follow:

Volume of solid = (Volume of water + solid) – (Volume of water)

Volume of solid = 10 – 8

Volume of solid = 2 mL

Therefore, the volume of the solid is 2 mL

Why Phenol is acidic in nature but benzene is not acidic in nature?

Answers

Hei, here it is !

Phenol is more acidic than cyclohexanol and acyclic alcohols because the phenoxide ion is more stable than the alkoxide ion. In an alkoxide ion, the negative charge is localized at the oxygen atom. But in a phenoxide ion, the negative charge is delocalized over the benzene ring.

Which of the following mixtures will react the fastest?

a. Iron DUST and 2 moles HCI
b. Iron DUST and 4 moles HCI
c. Solid Iron CUBE and 2 moles HCI
d. Solid Iron CUBE and 4 moles HCI


Answers

Answer:

I think the answer would be A.

Im stuck on these two questions anyone have the right answer?

Answers

17.) C 4-methylhex-1-ene

5.) D oct-3-ol-5-en

does anyone know this??

Answers

Answer: C2H6O

Explanation: It is C2H6O with a molar mass of 46.07 g/mol.

what is the atomic mass of an element with 40 protons 40 electrons and 46 neutrons

Answers

Answer:

The 40 represents the atomic number and the number of proton in Zirconium. The "Zr" on the tile is the symbol of the elementp


What does the number 7 mean in the following example-73Li?
a. The number of protons
b. The atomic mass
c. The atomic number
d. The number of electrons

Answers

Answer:

7 is the mass number of li and 3 is the atomic number

a 3

b 7

c 3

d 4

Boron has five protons and six neutrons. What is the atomic mass of boron?

A. 11
B. 10
C. 12
D. 1

Answers

Answer:

11

Explanation:

becauase 5 +6

Bro its 11..... . 6+5=11

Calculate the number of grams of Fe and the number of grams of Coz formed
when 0.150 kg of Fe2O3 reacts.

Answers to other questions on the sheet are appreciated!

Answers

Here are the answers, they’re also online

In the laboratory a student finds that it takes 103 Joules to increase the temperature of 12.6 grams of solid diamond from 22.4 to 39.4 degrees Celsius. The specific heat of diamond calculated from her data is

Answers

Answer:

The correct solution is "[tex]0.480 \ J/g^{\circ}C[/tex]".

Explanation:

Given:

q = 103 J

Mass,

m = 12.6 grams

Temperature,

[tex]T_1=22.4[/tex]

[tex]T_2=39.4[/tex]

[tex]\Delta T=T_2-T_1[/tex]

      [tex]=39.4-22.4[/tex]

      [tex]=17^{\circ}C[/tex]

Now,

⇒  [tex]C=\frac{q}{m\times \Delta T}[/tex]

⇒      [tex]=\frac{103}{12.6\times 17}[/tex]

⇒      [tex]=\frac{103}{214.2}[/tex]

⇒      [tex]=0.480 \ J/g^{\circ}C[/tex]

200 grams of iron (III) chloride reacts with ammonium carbonate [(NH4)2CO3] in the following equation.

FeCl3 + (NH4)2CO3 ---------> NH4Cl + Fe2(CO3)3



The number of grams of iron (III) carbonate Fe2(CO3)3 that will be produced is _ grams.



a
181
b
198
c
229
d
395

Answers

Answer. First things first... Balance the Chemical Equation

2FeCl3 + 3(NH4)2CO3 ---------> 6NH4Cl + Fe2(CO3)3

Its balanced Now.

200g of FeCl3 ---Given this... We can get jts reacting Moles

Mole = Mass/Molar Mass

Molar Mass of FeCl3 = 56 + (35.5)x3=162.5gmol-¹

Mole=200/162.5 =1.231moles of FeCl3

From the equation of Reaction

When 2mole of FeCl3 reacts.... It produces 1mole of Iron III carbonate [Fe2(CO3)3]

Since Mole ratio of reaction between both is 2:1

Therefore When 1.231moles of FeCl3 react....

1.231/2 moles of Fe2(CO3)3 will be produced.

= 1.231/2 = 0.616moles.

0.616Moles of Fe2(CO3)3 will be produced

Recall MASS =MOLE X MOLAR MASS

MOLAR MASS OF FE2(CO3)3= 56(2) + (60)(3)=292gmol-¹

MASS = 0.616 x 292 =179.872g ~ 180g of Fe2(CO3)3 Will Be Produced.

OPTION A SEEMS TO BE THE CLOSEST. THAT SHOULD BE OUR ANSWER. I MAY HAVE MISSED IT A BIT BECAUSE OF SOME APPROXIMATIONS.

BYE!

Answer:

[tex]FeCl₃ + (NH₄)₂CO₃ → NH₄Cl + Fe₂(CO₃)₃[/tex]

first balance the chemical equation

first balance the chemical equation[tex]2FeCl₃ + 3(NH₄)₂CO₃ → 6NH₄Cl + Fe₂(CO₃)₃[/tex]

2FeCl₃=2*162=324g

6NH₄Cl=6*53.5=321g

324 g of FeCl₃ gives 321 g of NH₄Cl

200g of FeCl₃ gives 321/324*200=198.14 g of NH₄Cl

in nearest value it is 198g/mole

The number of grams of ammonium chloride (NH4Cl) that will be produced is C.198___ grams.

he correct statements about thermal conductivity are: A. The thermal conductivity of metals is generally higher than that of liquids. B. The thermal conductivity of solids is generally higher than that of liquids. C. The thermal conductivity of gases is generally higher than that of liquids.

Answers

Answer: The correct statements about thermal conductivity are:

The thermal conductivity of metals is generally higher than that of liquids.The thermal conductivity of solids is generally higher than that of liquids.

Explanation:

The rate at which transfer of heat takes place from one object to another by conduction over a unit cross section area of a material is called thermal conductivity.

Hence, more is the distance between atoms of a substance less will be its thermal conductivity. This is because more is the space between molecules of a substance more will be their random motion due to which there will be less effective energy transport.

The thermal conductivity of metals is very high than liquids.

Also, the thermal conductivity of solids is generally higher than that of liquids.

As gases have more space between its molecules so they have less thermal conductivity.

Thus, we can conclude that the correct statements about thermal conductivity are:

The thermal conductivity of metals is generally higher than that of liquids.The thermal conductivity of solids is generally higher than that of liquids.

The base area of a pyramid is 1,225m2.if the pyramid is 11.3m high,what is it's volume​

Answers

Answer:

Volume = 4614 m³

Explanation:

The volume of a pyramide is given by the following formula:

Volume = 1/3 * base area * height

We are already given all the required information to calculate the volume by inputting the data:

Volume = 1/3 * 1225 m² * 11.3 mVolume = 4614 m³

The pyramid's volume is 4614 cubic meters.

How many moles of solute are in a 1.50 M solution of HCl with a volume of 7.98 liters?

Answers

Answer:

[tex]\boxed {\boxed {\sf x\approx 12.0 \ moles \ HCl}}[/tex]

Explanation:

Molarity is a measure of concentration in moles per liter.

[tex]molarity= \frac{moles \ of \ solute}{liters \ of solution}[/tex]

We know the solution has a volume of 7.98 liters and it has a molarity of 1.50 M HCl.

1 molar (M) is 1 mole per liter, so the molarity is also 1.50 moles of HCl per liter.

We know 2 values for the variables, but the value for moles of solute is unknown, so we use x.

molarity= 1.50 mol HCl/L moles of solute=xliters of solution = 7.98 L

Substitute the values into the formula.

[tex]1.50 \ mol \ HCl/L=\frac{x}{7.98 \ L}[/tex]

We are trying to solve for x, the moles of solute, so we must isolate the variable. It is being divided by 7.98 liters and the inverse of division is multiplication. Multiply both sides of the equation by 7.98 liters.

[tex]7.98 \ L *1.50 \ mol \ HCl/L=\frac{x}{7.98 \ L} * 7.98 \ L[/tex]

[tex]7.98 \ L *1.50 \ mol \ HCl/L=x[/tex]

The units of liters (L) cancel each other out.

[tex]7.98 *1.50 \ mol \ HCl=x[/tex]

[tex]11.97 \ mol \ HCl=x[/tex]

The original measurements of molarity and volume both have 3 significant figures, so our answer must have the same. For the number we found, that is the tenths place.

The 9 in the hundredth place tells us to round the 1 to a 2. We leave a 0 in the tenths place to ensure there are 3 significant figures.

[tex]12.0 \ mol \ HCl \approx x[/tex]

There are approximately 12.0 moles of solute in the solution.

List five general properties of organic
Compound

Answers

Answer:

Five general properties of organic  compounds:

Organic compounds include complex structures and high molecular weights.Organic  compounds have low melting points and boiling points. They are volatile in nature. They are generally insoluble in water but soluble in organic solvents. They are poor bad conductors of electricity.
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