What is the correct answer question

Answer:

26.5°C

Explanation:

We can solve this question using the equation:

q = m*S*ΔT

Where Q is heat gained in joules, m is the mass of the sample, S is specific heat and ΔT change in temperature.

With the sample A we can find specific heat of cobalt in order to find, in sample B, the ΔT and the final temperature:

Sample A:

q = m*S*ΔT

6.70J = 5.00g*S*(27.9°C-25.0°C)

0.462J/g°C = Specific heat of cobalt

Sample B:

q = m*S*ΔT

5.00J = 7.00g*0.462J/g°C*ΔT

1.5°C = ΔT

As the initial temperature of sample B is 25°C, final temperature is:

25°C + 1.5°C = 26.5°C

Answer:

Starch.

Explanation:

When the triiodide combine with starch, it forms dark blue colour. Amylose in starch is responsible for the occurrence of a deep blue color when the iodine is combine with the starch. The iodine molecule goes inside of the amylose coil which makes a linear triiodide ion complex that goes into the coil of the starch that leads to an intense blue-black color in the end so we can say that starch turns the colour into blue.

Answer: The number of milliliters of 654 mL for 0.587 M NaOH required to precipitate all of the [tex]Fe^{3+}[/tex] ions in 197 mL of 0.654 M [tex]FeCl_{3}[/tex] solution as [tex]Fe(OH)_{3}[/tex].

Explanation:

The reaction equation is as follows.

[tex]FeCl_{3}(aq) + 3NaOH(aq) \rightarrow Fe(OH)_{3}(s) + 3NaCl(aq)[/tex]

Therefore, moles of [tex]Fe(OH)_{3}[/tex] are calculated as follows.

Moles = Molarity of [tex]Fe(OH)_{3}[/tex]  [tex]\times[/tex] Volume (in L)

= 0.654 M [tex]\times[/tex] 0.197 L  

= 0.128 mol

Now, according to the given balanced equation 1 mole of [tex]FeCl_{3}(aq)[/tex] reacts with 3 moles of NaOH(aq). Hence, moles of [tex]Fe(OH)_{3}[/tex]  reacted are calculated as follows.

3 [tex]\times[/tex] 0.128 mol = 0.384 moles of NaOH

As moles of NaOH present are as follows.

Moles of NaOH = Molarity of NaOH [tex]\times[/tex] Volume (in L)

0.384 mol = 0.587 M [tex]\times[/tex] Volume (in L)

Volume (in L) = 0.654 L (1 L = 1000 mL) = 654 mL

Thus, we can conclude that the number of milliliters of 654 mL for 0.587 M NaOH required to precipitate all of the [tex]Fe^{3+}[/tex] ions in 197 mL of 0.654 M [tex]FeCl_{3}[/tex] solution as [tex]Fe(OH)_{3}[/tex].

Answer: The given chemical reaction can be classified as synthesis and exothermic.

Explanation:

A synthesis reaction is defined as the reaction where two small chemical species combine in their elemental state to form a single large chemical species.

Exothermic reactions are defined as the reactions in which heat is released by the reaction. The heat is written on the product side of the reaction.

For the given chemical reaction:

[tex]Mg(s)+O_2(g)\rightarrow MgO(s)+\text{heat}[/tex]

The above chemical reaction is a type of synthesis and exothermic as two substances in their elemental state are combining. Also, heat is getting released in the reaction.

Hence, the given chemical reaction can be classified as synthesis and exothermic.

Answer:

pOH = - log[OH-]

[OH-] = 0.6M

[tex]pOH \: = - log(0.6) \\ = 0.2218487496 \\ pH \: + pOH \: = 14 \\ pH \: + 0.221848749 = 14 \\ pH = 14 - 0.221848749 \\ = 13.77815125 \\ 13.8[/tex]

Explanation:

Do đó cấu hình electron của canxi là: 1s2 2s2 2p6 3s2 3p6 4s2.

Explanation:

C4H10 + 13/2O2 ---------> 4CO2 + 5H2O

so u can work out the amount of moles by doing

moles=mass/mr

mr of C4H10 is 12 × 4 + 10 =58

=7.269/58

= 0.125moles

Then u can use the molar ratio which is

6.5:4

0.125 ÷6.5 × 4 = 0.0769moles

hope this helps:)

Answer:

LiCl = 0.492 m

Explanation:

Molal concentration is the one that indicates the moles of solute that are contained in 1kg of solvent.

Our solute is lithium chloride, LiCl.

Our solvent is distilled water.

We do not have the mass of water, but we know the volume, so we should apply density to determine mass.

Density = mass / volume

Density . volume = mass

1 g/mL . 19.7 mL = 19.7 g

We convert g to kg → 19.7 g . 1 kg / 1000g = 0.0197 kg

Let's determine the moles of LiCl

0.411 g . 1 mol / 42.394 g = 9.69×10⁻³ moles

Molal concentration (m) = 9.69×10⁻³ mol / 0.0197 kg → 0.492 m

The molal concentration of the resulting solution is 0.492 m. The concentration number of moles of solute in one kg of solvent.

It is the measure of the concentration number of moles of solute in one kg of solvent.

To calculate the molal concentration first calculated the mass of [tex]\bold {LiCl}[/tex],

[tex]\rm \ mass = density \times volume[/tex]

Put the values,

m = 1 g/mL x  19.7 mL

m = 19.7 g     or

m = 0.0197 kg

Calculate the moles of LiCl:

[tex]n =\rm \dfrac { 0.411 \ g \times 1 mol }{ 42.394 \ g }\\\\n = 9.69\times 10^{-3} \ moles[/tex]

So, now the molal concentration,

[tex]m = \rm \dfrac { 9.69\times 10^{-3}\ mol} {0.0197 \ kg} \\\\m = 0.492[/tex]

Therefore, the molal concentration of the resulting solution is 0.492 m.

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Answer:

2NaCl + CuCO3

FeCl2 + BaSO4

CuCO3 + Ca(NO3)2

Explanation:

Presumably this is a double replacement reaction.

A+B + C+D → A+D + C+B

It seems I may be wrong so please try to work out the problem yourself to double check, keeping in mind the charges of each compound.

Answer:

B

Explanation:

AH is positive so the forward reaction is endothermic. Thus, increasing temperature would cause equilibrium to shift to the right as endothermic reaction favors higher temperature. This increases the yield of NO.

Answer:

Cuáles son las características de la luz y en qué consisten?

Explanation:

La luz es una radiación que se propaga en forma de ondas. Las ondas que se pueden propagar en el vacío se llaman ONDAS ELECTROMAGNÉTICAS. La luz es una radiación electromagnética

Answer:

Q was < K. Partial pressure of hydrogen decreased, iodine increased

Explanation:

After iodine was added the Q was [Select] K so the reaction shifted toward the Products [Select] ,The partial pressure of hydrogen [Select], Iodine [Select] |,and hydrogen iodide Decreased

Based on the equilibrium:

H2(g) + I2(g) ⇄ 2HI(g)

K of equilibrium is:

K = [HI]² / [H2] [I2]

Where [] are concentrations at equilibrium

And Q is:

Q = [HI]² / [H2] [I2]

Where [] are actual concentrations of the reactants.

When the reaction is in equilibrium, K=Q.

But as [I2] is increased, Q decreases and Q was < K

The only concentration that increases is [I2], doing partial pressure of hydrogen decreased, iodine increased

Answer:

–0.13 Pa.m²

Explanation:

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

Measurement (Pa.mm²) = –1.3×10⁵ Pa.mm²

Measurement (Pa.m²) =?

We can convert from Pa.mm² to Pa.m² by doing the following:

1 Pa.mm² = 1×10¯⁶ Pa.m²

Therefore,

–1.3×10⁵ Pa.mm² = –1.3×10⁵ Pa.mm² × 1×10¯⁶ Pa.m² / 1 Pa.mm²

–1.3×10⁵ Pa.mm² = –0.13 Pa.m²

Thus, –1.3×10⁵ Pa.mm² is equivalent to –0.13 Pa.m².

The complete equation will be:

[tex](-1.3\times 10^5 Pa.mm^2)\times 10^{-6}=(-0.13) Pa.m^2[/tex]

Explanation:

Given:

The equation to convert a measurement:

[tex](-1.3\times 10^5 Pa.mm^2)\times ? = ? Pa.m^2[/tex]

To find:

The missing part of the equation.

Solution:

[tex](-1.3\times 10^5 Pa.mm^2)\times ? = ? Pa.m^2[/tex]

On LHS the unit is in [tex]Pa. mm^2[/tex] and RHS the unit is in [tex]Pa.m^2[/tex] which means that we have to convert [tex]mm^2[/tex] to [tex]m^2[/tex]

In 1 millimeter there are 0.001 meters.

[tex]1 mm = 0.001 m\\1 mm^2=0.000001 m^2=10^{-6} m^2[/tex]

So, the complete equation will be:

[tex](-1.3\times 10^5 Pa.mm^2)\times 10^{-6}=(-0.13) Pa.m^2[/tex]

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Answer:

m = 20.9 g.

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to solve this problem by recalling both the Avogadro's number for the calculation of the moles in the given molecules of calcium phosphate and the molar mass of this compound in order to secondly calculate the mass as shown on the following setup:

[tex]m=4.05x10^{22}molecules*\frac{1mol}{6.022x10^{23}}*\frac{310.18g}{1mol}\\\\m=20.9g[/tex]

Regards!

Answer:

a. Na₃PO₄

b. NH₄Cl

c. FeCl₃

d. KClO₃

Explanation:

a. Sodium tetraoxophosphate(V) Na₃PO₄

3Na⁺ + PO₄³⁻ → Na₃PO₄

b. Ammonium Chloride NH₄Cl

NH₄⁺ + Cl⁻ → NH₄Cl

c. Iron(III)chloride

Fe³⁺ + Cl⁻ → FeCl₃

d. Potassium trioxochlorate(V) KClO₃

K⁺ + ClO₃⁻ → KClO₃

Answer:

i think its c because thats when the direction changes and you dont know where he went.                                                

Explanation:

Answer:

Explanation:

fluorine have gained one electron that is why the sign is -1. they both have different number of protons. They have different neutron numbers. F have 10 and O have 8.

hope this helps :)

Answer:

a

Explanation:

Answer:

according to the path shown in the figure it will start decreasing then again it will start increasing when the path will be nearer to the star.

Reason is gravitation force is indirectly proportional to the distance.

So, option B. decrease then increase is correct

There will be no oxygen in the product. Some of the oxygen will evaporate into the air.

Answer: Volume occupied by 3.00 moles of oxygen gas under the same condition is 3.75 L.

Explanation:

Given: [tex]n_{1}[/tex] = 4.00 moles,          [tex]V_{1}[/tex] = 5.0 L

[tex]n_{2}[/tex] = 3.00 moles,                 [tex]V_{2}[/tex] = ?

Formula used is as follows.

[tex]\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}[/tex]

Substitute the values into above formula as follows.

[tex]\frac{V_{1}}{n_{1}} = \frac{V_{2}}{n_{2}}\\\frac{5.0 L}{4.00 mol} = \frac{V_{2}}{3.00 mol}\\V_{2} = 3.75 L[/tex]

Thus, we can conclude that volume occupied by 3.00 moles of oxygen gas under the same condition is 3.75 L.

Answer:

D) a four-fold increase

Explanation:

According to Gay-Lussac's law, which states that the pressure of a given amount of gas is directly proportional to the temperature at a constant volume, the pressure increases with an increase in temperature.

According to this question, at a fixed volume, a four-fold increase in the temperature of a gas will lead to a four-fold increase in the pressure as well.

Answer:

[tex]Key=2.5x10^{-9}[/tex]

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to calculate the equilibrium constant value for the reverse reaction:

[tex]2CO_2(g) \rightleftharpoons 2CO(g) + O_2(g)[/tex]

By knowing that the equilibrium expression is actually:

[tex]Key =\frac{[CO]^2[O_2]}{[CO_2]^2} =\frac{1}{Keg}[/tex]

Thus, we plug in and solve for the inverse of Keq to obtain Key as follows:

[tex]Key =\frac{1}{4.0x10^{-10}}\\\\Key=2.5x10^{-9}[/tex]

Regards!

Answer:

M = 3.69 M.

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to calculate the molar concentration of the 1.29 moles of KCl in 350 mL of solution by recalling the mathematical definition of molarity as the division of the moles by the volume in liters, in this case 0.350 L; thus, we proceed as follows:

[tex]M=\frac{1.29mol}{0.350L}\\\\M=3.69M[/tex]

Which gives molar units, M, or just mol/L.

Regards!

Answer:

a) 0.15 mol.

b) 8.95 g.

Explanation:

Hello there!

In this case, according to the given information, it is possible for us to infer this problem is solved by using the ideal gas equation:

[tex]PV=nRT[/tex]

And proceed as follows:

a) Here, we solve for the moles, n,  as follows:

[tex]n=\frac{PV}{RT} \\\\n=\frac{0.50atm*4.5L}{0.08206\frac{atm*L}{mol*K}*178K} \\\\n=0.15mol[/tex]

b) for the calculation of the mass, we recall the molar mass of butane, 58.12 g/mol, to obtain:

[tex]0.15mol*\frac{58.12g}{1mol} =8.95g[/tex]

Regards!

Answer:

[tex]pH = - log[H {}^{ + } ] \\ = - log(0.0000067) \\ pH = 5.17[/tex]

Answer:

A. Glucose

Explanation:

Glucose is a monomer and not a polymer. So, option (A) is not a polymer.

Glucose is not a polymer because it is a kind of molecule while Starch , cellulose and DNA are polymers.

The correct answer is option A. Glucose.

Answer:

the Molecular formula will be; C10H14O

Explanation:

Given the data in the question;

Chrysanthenone is an unsaturated ketone,

it has M+ = 150 and contains 2 double bond(s) and 2 ring(s).

molecular formula = ?

we know that ketone contain 1 oxygen and mass of oxygen is 16

so mass of the C and H remaining will be;

⇒ 150 - 16 = 134

Now we determine the number of C atoms;

⇒ 134 / 13 = 10

hydrocarbon with 10 hydrogen atom have CnH2n+2 means

⇒ ( 10 × 2 ) +2 = 22 hydrogens

But then we have 3 unsaturation meaning 6 hydrogens less and also we have ring meaning 2 more hydrogens

⇒ 22 - 6 - 2 = 14

Hence the Molecular formula will be; C10H14O

Answer:

if it is pure, the substances is either an element or a compound. if a substance is not chemically pure, it is either a heterogeneous mixture or a homogeneous mixture. if its composition is uniform throughout, it is a homogeneous.