A student conducted an experiment 4 times. His results were very close to each other each time he ran the experiment and
were very close to the true or actual value. His results showed
A. None of these answers are correct
B. poor accuracy and poor precision
C. good accuracy and good precision
D. poor accuracy and good precision
E. good accuracy and poor precision

Answer:

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Answer:

By how many times would you expect Al2(SO4)3 to depress the F.P of water compared to sucrose C12H22011 ?.

Explanation:

The freezing point of a pure solvent decreases further by adding a nonvolatile solute.

This is called depression in freezing point.

When an ionic solute is dissolved then the depression in the freezing point is proportional to the number of ions present in the solution.

In aluminum sulfate, there are five ions formed as shown below:

[tex]Al_2(SO_4)_3(aq)->2Al^3^+(aq)+3SO_4^2^-(aq)[/tex]

But sucrose is a covalent compound and it does not undergo dissociation.

Hence, aluminum sulfate decreases the freezing point of water by five times compared to sucrose.

Explanation:

Explanation: The hypothesis is a prediction, but it involves more than a guess. Most of the time, the hypothesis begins with a question which is then explored through background research. It is only at this point that researchers begin to develop a testable hypothesis.

(Unless you are creating an exploratory study, your hypothesis should always explain what you expect to happen)

Answer:

The equivalent weight of calcium hydroxide is 1/2 he mass of a mol of calcium hydroxide. 1 mol Ca(OH)2 = 74 grams Ca(OH)2 ; 1 equivalent Ca(OH)2 = 37 grams Ca(OH)2......

Explanation:

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Answer:

Copper iodide. I think

Answer:

hope it helps

Explanation:

a) Since this is a double displacement reaction, we write the balanced equation as

[tex]2AgNO_3(aq) + CaCl_2(aq) \\ \rightarrow 2AgCl(s) + Ca(NO_3)_2(aq)[/tex]

b) Next we find the number of moles of AgNO3 in the solution.

[tex](0.005\:\text{L})(0.500\:M\:AgNO_3) \\ = 0.0025\:\text{mol}\:AgNO_3[/tex]

Next, use the molar ratio to find the necessary amount of CaCl2 to react with the AgNO3:

[tex]0.0025\:\text{mol}\:AgNO_3× \left(\dfrac{1\:\text{mol}\:CaCl_2}{2\:\text{mol}\:AgNO_3} \right)[/tex]

[tex]= 0.00125\:\text{mol}\:CaCl_2[/tex]

The volume of 0.500 M solution of CaCl2 necessary to react all of the given AgNO_3 is then

[tex]V = \dfrac{0.00125\:\text{mol}\:CaCl_2}{0.500\:\text{M}\:CaCl_2}[/tex]

[tex]= 0.0025\:\text{L} = 2.5\:\text{mL}\:CaCl_2[/tex]

c) The theoretical yield can then be calculated as

[tex]0.0025\:\text{mol}\:AgNO_3 × \left(\dfrac{2\:\text{mol}\:AgCl}{2\:\text{mol}\:AgNO_3} \right)[/tex]

[tex]= 0.0025\:\text{mol}\:AgCl[/tex]

Converting this amount of AgCl into grams, we get

[tex]0.0025\:\text{mol}\:AgCl × \left(\dfrac{143.32\:\text{g}\:AgCl}{1\:\text{mol}\:AgCl} \right)[/tex]

[tex]= 0.358\:\text{g}\:AgCl[/tex]

Answer:

For 1: The product is phosphoric acid and the solution is acidic in nature.

For 2: The product is sodium hydroxide and the solution is basic in nature.

For 3: The product is nitric acid and the solution is acidic in nature.

Explanation:

For the given options:

(1): When diphosphorus pentoxide reacts with water, it leads to the formation of phosphoric acid, which makes the solution acidic in nature.

The chemical equation for the reaction follows:

[tex]P_4O_{10}+6H_2O(l)\rightarrow 4H_3PO_4(aq)[/tex]

(2): When disodium oxide reacts with water, it leads to the formation of sodium hydroxide, which makes the solution basic in nature.

The chemical equation for the reaction follows:

[tex]Na_2O+H_2O(l)\rightarrow 2NaOH(aq)[/tex]

(3): When dinitrogen pentoxide reacts with water, it leads to the formation of nitric acid, which makes the solution acidic in nature.

The chemical equation for the reaction follows:

[tex]3N_2O_5+3H_2O(l)\rightarrow 6HNO_3(aq)[/tex]

Answer:

Explained below.

Explanation:

In order to extract lead from lead oxide, we need to add carbon from coke to the lead oxide.

We will need;

A bunsen burner

A test tube

Charcoal

First step is to heat charcoal in an oxygen free environment. The safety measure here to ensure an oxygen free environment is to add some zinc metal powder into the test tube in order to remove any atmospheric oxygen inside the container.

Secondly, we will now put charcoal inside the test tube and turn on the bunsen burner to heat it until coke is formed.

Thirdly, we now introduce lead oxide into the coke inside the test tube and the carbon in the coke reacts with the lead oxide to produce lead and carbon dioxide.

Throughout all this process, since we required an oxygen free environment inside the test tube, whenever the test tube is opened, its neck must immediately be warmed by heat with the tube placed in a horizontal direction or very close to being in that horizontal direction so that any movement of air moves outwards from the tube.

Answer:

It has a negative charge and is located in orbitals around the nucleus

Explanation:

The statement describes an electron is " It has a negative charge and is located in orbitals around the nucleus."

The electron would be a subatomic particle with a negatively one elementary charge electric charge.

Protons, that have a positive charge, as well as neutrons, which have no electrical charge, make up the nucleus. Quarks were subatomic particles that make up protons but also neutrons.

Electrons were present surrounding the atom's nucleus, in contrast to protons as well as neutrons, that are contained within the nucleus at its core. Negative electrons were drawn to the positive nucleus since the electric charges of opposite polarity attract one another.

To know more about electrons and nucleus.

https://brainly.com/question/23366064

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Answer:

SN1 mechanism

Explanation:

The mechanism of this reaction is shown in the image attached.

The Di- n- pentyl ether is first protonated. The CH3(CH2)4OH is now a good leaving group as shown.

The attack of the bromide ion on the cation formed completes the mechanism to yield 1- bromopentane as shown in the mechanism.

Answer:

option a

hope helps you

have a great day

Answer:

(a) The potential near its surface is 45 * 10^6 V.

(b) The distance from which its center is the potential 1.00 MV is 45 m.

(c) Its energy in MeV when the atom is at the distance found in part b is 132 MeV.

Explanation:

Note: This question is not complete. The complete question is therefore provided before answering the question.

A research Van de Graaff generator has a 2.00-m diameter metal sphere with a charge of 5.00 mC on it. (a) What is the potential near its surface?

(b) At what distance from its center is the potential 1.00 MV?

(c) An oxygen atom with three missing electrons is released near the Van de Graaff generator. What is its energy in MeV when the atom is at the distance found in part b?

The explanation of the answer is now provided as follows:

(a) What is the potential near its surface?

Q = Charge on the generator = 5 mC = 5 * 10^(-3)C

r = Sphere radius = 2 / 2 = 1 m

k = Constant of the electric force = 9 * 10^(9) N . m^2 / C^2

Therefore, the electric potential of a point charge can be calculated as follows:

V = kQ / r

V = (9 * 10^9 * 5 * 10^(-3)) / 1 = 45 * 10^6 V

Therefore, the potential near its surface is 45 * 10^6 V.

(b) At what distance from its center is the potential 1.00 MV?

This implies the distance where the potential is 1 MV.

Since the electric potential of a point charge is as follows:

V = kQ / r

Therefore, we can solve for r and estimate it as follows:

R = kQ / V = (9 * 10^9 * 5 * 10^(-3)) / 1 * 10^6 = 45 m

Therefore, the distance from which its center is the potential 1.00 MV is 45 m.

(c) An oxygen atom with three missing electrons is released near the Van de Graaff generator. What is its energy in MeV when the atom is at the distance found in part b?

The link between the potential difference and electrical potential energy can be stated as follows:

ΔV = ΔU / q

Therefore, we have:

ΔU = qΔV = q(Va - Vb) = 3 * (45 – 1) = 132 MeV

Therefore, its energy in MeV when the atom is at the distance found in part b is 132 MeV.

Answer:

0.5024 g

Explanation:

Step 1: Calculate the concentration of H⁺

We will use the definition of pH.

pH = -log [H⁺]

[H⁺] = antilog -pH = antilog -12.40 = 3.981 × 10⁻¹³ M

Step 2: Calculate the concentration of OH⁻

We will use the ionic product of water expression.

[H⁺] [OH⁻] = 10⁻¹⁴

[OH⁻] = 10⁻¹⁴/[H⁺] = 10⁻¹⁴/3.981 × 10⁻¹³ = 0.02512 M

Step 3: Calculate the initial concentration of NaOH

NaOH is a strong base and the molar ratio of NaOH to OH⁻is 1:1. Thus, the initial concentration of NaOH is 1/1 × 0.02512 M = 0.02512 M.

Step 4: Calculate the moles of NaOH

We will use the definition of molarity.

M = moles of NaOH/liters of solution

moles of NaOH = M × liters of solution

moles of NaOH = 0.02512 mol/L × 0.5000 L = 0.01256 mol

Step 5: Calculate the mass of 0.01256 moles of NaOH

The molar mass of NaOH is 40.00 g/mol.

0.01256 mol × 40.00 g/mol = 0.5024 g

Answer:

64 g

Explanation:

Step 1: Write the balanced equation

2 Na + Cl₂ ⇒ 2 NaCl

Step 2: Calculate the moles corresponding to 25 g of Na

The molar mass of Na is 22.98 g/mol.

25 g × 1 mol/22.98 g = 1.1 mol

Step 3: Calculate the moles of NaCl formed from 1.1 moles of Na

The molar ratio of Na to NaCl is 2:2. The moles of NaCl formed are 2/2 × 1.1 mol = 1.1 mol.

Step 4: Calculate the mass corresponding to 1.1 moles of NaCl

The molar mass of NaCl is 58.44 g/mol.

1.1 mol × 58.44 g/mol = 64 g

Answer: The number of series in Mendeleev's Periodic table is 12.

Explanation:

Horizontal rows present in the periodic table are called periods. Vertical rows in the periodic table are called series.

Mendeleev gave periodic table in the year 1869 by arranging elements according to their atomic weights a in tabular form.  

Mendeleev's periodic table depicts 12 periods/series.

Thus, we can conclude that the number of periods/series in Mendeleev's Periodic table is 12.

Answer:

Excluding any secondary chemical reactions,

which would be more effective as an antifreeze; a

solution containing

Select one:

25m CH3OH

the combination of 25m CH3OH and 25m

KCI.

25m KCI.

Explanation:

Antifreeze is the one that reduces the freezing point of a solvent further and will not allow the solvent to freeze.

Among the given options, the correct option is:

25 m CH3OH and 25m KCl.

Since, KOH is a strong electrolyte and dissociates into two ions.

So, the freezing point of solvent decreases further.

Answer:

dispersion force

Explanation:

Answer:

To 318.18 mL would you need to dilute 20.0 mL of a 1.40 M solution of LiCN to make a 0.0880 M solution of LiCN

Explanation:

Dilution is the reduction of the concentration of a chemical in a solution and consists simply of adding more solvent.

In a dilution the amount of solute does not vary. But as more solvent is added, the concentration of the solute decreases, as the volume (and weight) of the solution increases.

In a solution it is fulfilled:

Ci* Vi = Cf* Vf

where:

In this case:

Replacing:

1.40 M* 20 mL= 0.088 M* Vf

Solving:

[tex]Vf=\frac{1.40 M* 20 mL}{0.088 M}[/tex]

Vf= 318.18 mL

To 318.18 mL would you need to dilute 20.0 mL of a 1.40 M solution of LiCN to make a 0.0880 M solution of LiCN

Answer:

$20

ASAP PROJECT

Answer:

C₆H₆

Explanation:

Each border of the figure represents 1 atom of carbon. We have 6 borders = 6 atoms of carbon.

Each atom of carbon form 4 bonds. All the carbons are doing a double bond and a single bond with other carbons. That means are bonded 3 times. The other bond (That is not represented in the figure. See the image) comes from hydrogens. As we have 6 carbons that are bonded each 1 with one hydrogen. There are six hydrogens and the molecular formula is:

This structure is: Benzene

Answer:

Danger

Explanation:

Answer:

0.64 m

Explanation:

Given that;

1L = 0.001 cubic metre

Then;

263 L = 263 L × 0.001 cubic metre/1L

= 0.263 cubic metre

Volume of a cube = l^3

l= 3√V

l= 3√0.263 cubic metre

l= 0.64 m

Answer:

Towards the big bully

Explanation:

If a big bully and a small child are involved in a thug of war, it is clear that the bully is stronger than the child and he/she will pull the rope used in the thug of war with a greater force.

By so doing, the ball attached at the centre of the rope will naturally be drawn towards the stronger bully.

Answer: The correct option is ALL OF THE ABOVE.

Explanation:

TITRATION is a type of volumetric analysis which is used for determining the concentration of solutions. In this process a specific volume of a solution is placed in a conical flask by means of a pipette and small quantities of a second solution is slowly added from a burette until the end point is reached. This is determined by a means of an indicator which shows a characteristic colour change.

During titration, the following precautions should be followed to avoid errors and maintain standardisation in the experiment.

--> Any air bubble in the burette and pipette must be removed during measurement

--> the burette tap should be tightened to avoid leakage.

--> Remove the funnel from the burette before taking any reading to avoid errors in reading the volume.

--> use the base solution such as Sodium Hydroxide Solution to rinse the burette after washing with soap and tap water:

• to remove any air bubble and fill it's tip

• to remove any residual liquid from the water and soap solution which may interfere with the results of the experiment.

• to check if the burette is in good condition.

Therefore all of the above options to the question are correct.

Answer: If a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.

Explanation:

The relation between energy and wavelength is as follows.

[tex]E = \frac{hc}{\lambda}\\[/tex]

This means that energy is inversely proportional to wavelength.

As it is given that energy of a hydrogen atom and a helium atom is same.

Let us assume that [tex]E_{hydrogen} = E_{helium} = E'[/tex]. Hence, relation between their wavelengths will be calculated as follows.

[tex]E_{hydrogen} = \frac{hc}{\lambda_{hydrogen}}[/tex]    ... (1)

[tex]E_{helium} = \frac{hc}{\lambda_{helium}}[/tex]         ... (2)

Equating the equations (1) and (2) as follows.

[tex]E_{hydrogen} = E_{helium} = E'\\\frac{hc}{\lambda_{hydrogen}} = \frac{hc}{\lambda_{helium}} = E'\\\lambda_{helium} = \lambda_{hydrogen} = E'[/tex]

Thus, we can conclude that if a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.

Answer:

the product is Mg(Clo3)2 + AgI

Answer:

 Lewis structure of Hydronium ion is shown below :                          

Explanation:

Lewis structure : It is a representation of valence electrons on the atoms in a molecule

Here , Hydronium ion is given , which contains 1 atom of oxygen and 3 atoms of hydrogen .

Oxygen has a total of 6 valence electrons and hydrogen contains 1 valence electron .

Oxygen share its 3 valence electrons with 3 hydrogen atoms and left with 3 valence electrons. From these three valence  electrons of oxygen atom  two electrons will be shown as a pair of electrons on oxygen atom but a single electron can not be shown . So , to simplify this, one positive charge is shown overall .  

Resonance structure will be same as the hybrid structure because all  three atoms are same , that is hydrogen .

Answer:

a. [tex]Ag^0[/tex]

b. [tex]Ag^{+}[/tex]

c. [tex]Ca^{2+}F_2^-[/tex]

d. [tex]H_2^+S^{2-}[/tex]

e. [tex](C^{4+}O_3^{2-})^{-}[/tex]

f. [tex](Cr^{6+}O_4^{2-})^{2-}[/tex]

g. [tex]Cl_2^0[/tex]

h. [tex]Fe^0[/tex]

i. [tex]Cu^{2+}Cl_2^-[/tex]

j. [tex]C^{4-}H_4^+[/tex]

Explanation:

Hello there!

In this case, according to the concept of charge balance, which tell us that the overall charge is zero for any compound, except ions, it turns out possible to proceed as follows:

a. [tex]Ag^0[/tex]

b. [tex]Ag^{+}[/tex]

c. [tex]Ca^{2+}F_2^-[/tex]

d. [tex]H_2^+S^{2-}[/tex]

e. [tex](C^{4+}O_3^{2-})^{-}[/tex]

f. [tex](Cr^{6+}O_4^{2-})^{2-}[/tex]

g. [tex]Cl_2^0[/tex]

h. [tex]Fe^0[/tex]

i. [tex]Cu^{2+}Cl_2^-[/tex]

j. [tex]C^{4-}H_4^+[/tex]

Keep in mind lonely elements have 0 as their oxidation state.

Regards!

Answer:

The correct answer is "-268.667°C".

Explanation:

Given:

Temperature,

= 4.483 K (below)

Now,

The formula of temperature conversion will be:

⇒ [tex]T(^{\circ} C)=T(K)-273.15[/tex]

By putting the values, we get

⇒            [tex]=4.483-273.15[/tex]

⇒            [tex]=-268.667^{\circ} C[/tex]

Thus the above is the correct answer.