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Which number belongsin the space labeled X?
O5
O7
O8
O 10

Answer:

The correct answer is HBr<NH4Br<KBr<NaCH3CO2<NaOH.

Explanation:

When salt is added to the water, the formation of acid and base takes place. The pH helps in predicting the basicity, acidity, and neutrality of a compound.

It is known that NaOH is a strong base, thus, its solution will be basic, and therefore, the pH of NaOH will be greater than 7.

The solution of HBr will be acidic as HBr is the strong acid, thus, its pH will be less than 7.

In dissolving NaCH3CO2 in water, the formation of CH3COOH, which is a weak acid, and NaOH that is, a strong base takes place. Therefore, as NaOH is the strong base, the solution will be basic, and the pH of NaCH3CO2 will be greater than 7.

On dissolving KBr in water, HBr, that is, a strong acid, and KOH, that is, a strong base is produced. Therefore, as HBr is the strong acid, and KOH is the strong base, the solution will be neutral. Thus, the pH of KBr will be equivalent to 7.

On dissolving NH4Br in water, the formation of HBr, that is, strong acid, and NH4OH, that is, the weak base takes place. Therefore, as HBr is the strong acid, the solution will be acidic, and the pH of NH4Br will be less than 7.

Hence, the increasing order of pH of 0.10 M aqueous solution will be,

HBr<NH4Br<KBr<NaCH3CO2<NaOH

The order of increasing pH of the solutions is; HBr < NH4Br < KBr < NaCH3CO2 < NaOH.

pH is a number that indicates the degree of acidity or alkalinity of a substance. The pH scale ranks from 0 - 14. 0 - 6.9 indicates acidity, 7 indicates neutrality while 8 - 14 indicates alkalinity.

The order of increasing pH of the solutions is; HBr < NH4Br < KBr < NaCH3CO2 < NaOH. Recall that NH4Br yields an acidic solution while NaCH3CO2 yields a basic solution.

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Answer:

c. electrons of the transition metal ion are excited to higher energies.

Explanation:

Answer:

Density = 0.17 g/L

Explanation:

It is given that,

Volume of the inflated balloon filled with Helium, [tex]V=2.2\times 10^3\ L[/tex]

Mass, m = 374 g

We need to find the density of helium. It is equal to its mass per unit volume. It can be given by :

d =m/V

[tex]d=\dfrac{374\ g}{2.2\times 10^3\ L}\\\\=0.17\ g/L[/tex]

So, the density of helium in the balloon is 0.17 g/L.

Answer:

C

Explanation:

You can’t round a phone number or Pin code

why would you round your birth year?

Answer:

A.True

Explanation:

Hope it's answered you plz mark as Brainlist

Answer:

[tex]M_{K^+}=2.1M[/tex]

Explanation:

Hello!

In this case, since we know the initial and final concentrations and the added volume of water, we can write:

[tex]3.50M*V_1=0.700M(0.210L+V_1)[/tex]

Which can be solved for the initial volume as follows:

[tex]3.50M*V_1-0.700M(0.210L+V_1)=0\\\\3.50V_1-0.147-0.7V_1=0\\\\2.8V_1=0.147\\\\V_1=\frac{0.147}{2.8}=0.0525L[/tex]

It means that the final volume is:

[tex]V_2=0.210L+0.0525L=0.2625L[/tex]

Next, we compute the moles of potassium phosphate in solution:

[tex]n_{K_3PO_4}=0.2625L*0.700\frac{molK_3PO_4}{L}=0.184molK_3PO_4[/tex]

Then, since 1 mol of potassium phosphate has 3 moles of potassium (K's subscript), we compute the moles of potassium ions:

[tex]n_{K^+}=0.184molK_3PO_4*\frac{3molK^+}{1molK_3PO_4}=0.551molK^+[/tex]

Finally, the concentration of potassium ions turns out:

[tex]M_{K^+}=\frac{0.551molK^+ }{0.2625L}\\\\ M_{K^+}=2.1M[/tex]

Regards!

Answer:

OB

Explanation:

wat does aquire mean

Answer:

a

Explanation:

a damaged stem

Answer:

yeah they're both balanced out

Answer:

The answer is: 5co2

The products will be:

CO2

SO2

H2O

Answer:

c, d, e

Explanation:

Got it right on edge

Answer:

2.07 × 10³ cal

Explanation:

Step 1: Given and required data

Step 2: Calculate the change in the temperature experienced by the aluminum piece

ΔT = 92.0 °C - 37.0 °C = 55.0 °C

Step 3: Calculate the heat required (Q)

We will use the following expression.

Q = c × m × ΔT

Q = 0.215 cal/g.°C × 175 g × 55.0 °C

Q = 2.07 × 10³ cal

Answer:

pharynx > larynx>trachea> bronchi>alveoli   (so B)

Explanation:

nasal cavities (or oral cavity) > pharynx > trachea > primary bronchi (right & left) > secondary bronchi > tertiary bronchi > bronchioles > alveoli (site of gas exchange)

Explanation:

when the current passes through a conductor the electrons have to face the resistance of the conductor which results in the loss of energy and this loss of energy gets converted into heat energy and it is called heating effect.good night.hope it will help uh.

Answer:

a. HCl.

b. 0.057 g.

c. 1.69 g.

d. 77 %.

Explanation:

Hello!

In this case, since the reaction between magnesium and hydrochloric acid is:

[tex]Mg+2HCl\rightarrow MgCl_2+H_2[/tex]

Whereas there is 1:2 mole ratio between them.

a) Here, we can identify the limiting reactant as that yielded the fewest moles of hydrogen gas product via the 1:1 and 2:1 mole ratios:

[tex]n_{H_2}^{by\ HCl}=0.025L*2.27\frac{molHCl}{1L}*\frac{1molH_2}{2molHCl} =0.0284molH_2\\\\n_{H_2}^{by\ Mg}=2.38gMg*\frac{1molMg}{24.3gMg}*\frac{1molH_2}{1molMg}=0.0979molH_2[/tex]

Thus, since hydrochloric yields fewer moles of hydrogen than magnesium, we realize it is the limiting reactant.

b) Here, we use the molar mass of gaseous hydrogen (2.02 g/mol) to compute the mass:

[tex]m_{H_2}=0.0284molH_2*\frac{2.02gH_2}{1molH_2}=0.057gH_2[/tex]

c) Here, we compute the mass of magnesium associated with the yielded 0.0248 moles of hydrogen:

[tex]m_{Mg}^{reacted}=0.0284molH_2*\frac{1molMg}{1molH_2}*\frac{24.3gMg}{1molMg} =0.690gMg[/tex]

Thus, the mass of excess magnesium turns out:

[tex]m_{Mg}^{excess}=2.38g-0.690g=1.69gMg[/tex]

d) Finally, we compute the percent yield, considering 0.044 g is the actual yield and 0.057 g the theoretical yield:

[tex]Y=\frac{0.044g}{0.057g} *100\%\\\\Y=77\%[/tex]

Best regards!

a) The limiting reactant would be HCl

From the equation of the reaction:

[tex]Mg (s) + 2 HCl (aq) ---> MgCl_2 (aq) + H_2 (g)[/tex]

The mole ratio of Mg to HCl is 1:2.

Mole = mass/molar mass = molarity x volume

Mole of Mg = 2.38/24.3

                     = 0.098 moles

Mole of HCl = 2.27 x 25/1000        

                     = 0.057 moles

Thus, HCl is limiting while Mg is in excess.

b) Since the mole ratio of HCl to H2 is 2:1:

Mole of H2 produced = 0.057/2

                                    = 0.028 moles

Mass of H2 produced = mole x molar mass

                                    = 0.028 x 2

                                     = 0.057 g

c) Actual mole of Mg that should react = 0.057/2

                                                                    = 0.028 moles

Excess mole of Mg = 0.098 - 0.028

                                   = 0.07

Mass of excess Mg = 0.07 x 24.3

                                 = 1.701 g

d) Percentage yield if 0.044 g of hydrogen is obtained = yield/theoretical x 100

                     = 0.044/0.057 x 100

                       = 77.19%

Answer:

3900 mol Pb

General Formulas and Concepts:

Chemistry - Atomic Structure

Explanation:

Step 1: Define

8.1 × 10⁵ g Pb

Step 2: Identify Conversions

Molar Mass of Pb - 207.2 g/mol

Step 3: Convert

[tex]8.1 \cdot 10^5 \ g \ Pb(\frac{1 \ mol \ Pb}{207.2 \ g \ Pb} )[/tex] = 3909.27 mol Pb

Step 4: Check

We are given 2 sig figs. Follow sig fig rules and round.

3909.27 mol Pb ≈ 3900 mol Pb

Answer:

Mass = 8.46 g

Explanation:

Given data:

Mass of water produced = ?

Mass of glucose = 20 g

Mass of oxygen = 15 g

Solution:

Chemical equation:

C₆H₁₂O₆ + 6O₂     →   6H₂O + 6CO₂

Number of moles of glucose:

Number of moles = mass/molar mass

Number of moles = 20 g/ 180.16 g/mol

Number of moles = 0.11 mol

Number of moles of oxygen:

Number of moles = mass/molar mass

Number of moles = 15 g/ 32 g/mol

Number of moles = 0.47 mol

now we will compare the moles of water with oxygen and glucose.

               C₆H₁₂O₆           :            H₂O

                   1                   :              6

                 0.11                :           6/1×0.11 = 0.66

                   O₂               :            H₂O

                   6                   :              6

                 0.47                :           0.47

Less number of moles of water are produced by oxygen thus it will limit the yield of water and act as limiting reactant.

Mass of water produced:

Mass = number of moles × molar mass

Mass = 0.47 mol  ×18 g/mol

Mass = 8.46 g

The reaction is missing, so i have attached it.

Answer:

C. An intramolecular aldol condensation

Explanation:

From the attached image showing the reaction, we can see that the left hand side of the reaction has 2 carbonyl groups which are the double bonds attached to the oxygen atoms.

Now, on the right hand side, we can see that a six member ring has been formed.

This 6 member ring is produced because one of the carbonyls on the left hand side was deprotonated at the alpha position thereby serving as a nucleophile, which then attacks the carbon in the other carbonyl.

This process is possible because it underwent the processes of deprotonation, intramolecular aldol addition, proton transfer and elimination to yield the right hand side product which is ɑ,β-unsaturated carbonyl compound.

Thus, the correct answer is option C

The net force = -5 N

The direction : to the left(negative sign)

Net force : the sum of all forces acting on an object

Force is a vector quantity that has both magnitude and direction,

We agree that the move up and to the right is a positive sign, while down and to the left is a negative sign.

The direction of the force (horizontal motion) is to the right (+32 N), and to the left (-37 N), so the net force :

[tex]\tt \sum F=F~right-F~left\\\\\sum F=32-37\\\\\sum F=-5~N[/tex]

Answer:

C

Explanation:

Metals are good conductors of heat

Answer:

18.2g/mol is the molar mass of the unknown solid assuming change in freezing point is 2.5°C

Explanation:

In this problem, there is no value of the freezing point depression and the constant for benzene, if:

Freezing point decreases by 2.5°C

And freezing point depression constant for benzene is 5.12°C/m

We can solve the problem as follows:

The freezing point depression is a colligative property that follows the equation:

ΔT = kf*m*ï

Where ΔT is change in temperature (We are assuming is 2.5°C)

Kf is freezing point depression constant for benzene (5.12°C/m)

m is molality of solution (Moles solute / kg solvent)

i is Van't hoff factor (For all solutes dissolved in organic solvents = 1)

Solving for m:

2.5°C = 5.12°C/m*m*1

m = 0.4883m

As molality is defined as moles of solute / kg of solvent and kg of solvent are 0.3632kg:

0.4883m = moles solute / 0.3632kg

0.177 moles of solute

Molar mass is defined as the mass of one mole of substance. Thus, molar mass of an unknown solid is:

3.232g / 0.177 moles of solute =

Answer:

pH = 4

Explanation:

Step 1: Given data

Concentration of H⁺ ions in the solution ([H⁺]): 10⁻⁴ M

Step 2: Calculate the pH of the solution

We will use the definition of pH.

pH = -log [H⁺]

pH = -log 10⁻⁴ M

pH = 4

The pH of the solution is 4. Considering the pH scale, given the pH is lower than 7, the solution is acidic.

Answer:

The crushed tablet dissolves fastest among the three forms.

Explanation:

The experiment is aimed at determining the effect of surface area of reactants on reaction rate.

Sodium bicarbonate tablets are provided and divided into three groups of consisting of three trials each. The temperature of the water is kept constant at 20°C. The first group consists of three tablets of sodium bicarbonate dissolved in individual trials in water. The second group consists of three quarter tablets of sodium bicarbonate dissolved in individual trials in water. The third group consists of three crushed tablets of sodium bicarbonate dissolved in individual trials in water.

The results shows that the average time for the dissolution of the first group is 51 seconds; the second group is 42 seconds while the third group is 17 seconds.

Therefore, it can be concluded that increasing the surface area of reactants increases the rate of reaction. This is because more reactant molecules are exposed for dissolution by water with increase in surface area.

Answer:

cold water

Explanation:

Answer:

A

Explanation:

Answer:

B. The western coast of the united states

Explanation:

I'm not sure if its correct but its pretty simple to understand, if you look at the arrows red represents heat, and blue represents cold,  the red arrows (warm climate) is at the left more towards the U.S, therefore looking at the guide of North West South and East, it is at the western coast of the u.s

Hope this help! <3

Because any natural element used in the cathode produced negative particles that bent to a positive charge, scientists concluded that ll atoms contained negative electrons.

A polarized electrical device's cathode is the electrode from which a regular current exits. The abbreviation CCD, which stands for Cathode Current Departs, might be used to remember this definition. Positive charges move in the direction described by a conventional current.

A cathode is a drawback. As an electron donor, it functions. It serves as an acceptor of electrons. The anode of an electrolytic cell is where the oxidation reaction occurs.

The negatively charged ions are drawn to the cathode, which is the negative electrode. Lead ions travel through the metal use negatively charged terminal of the battery and onto the lead ions because metal ions are usually positive. There must be a way to remember cathodes and anodes, cations and anions.

Thus, option A is correct.

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Answer:

Lathanum .

Atomic number = 57

Symbol = La

Atomic weight = 138.9

No of energy orbitals = 6

Electronic configuration

[tex][Xe]6s^25d^1[/tex]

Answer:

It should be A) +5

Explanation:

Answer:

%Sgr = 1% (1 sig.fig.)

Explanation:

mass water = 350ml x 0.975g/ml = 341.25g

mass sugar added = 4g

solution mass = 341.25g + 4g = 345.25g

%sugar = (4g/345.25g)·100% = 1.1586% ≅ 1% (1 sig.fig)

The percent composition by the mass of the sugar solution is:

e. 1.16 %

This can be calculated by using mass of sugar.

Mass of water = 350ml x 0.975g/ml = 341.25g

Mass of sugar added = 4g

Total solution's mass = 341.25g + 4g = 345.25g

%sugar = (4g/345.25g)·100%

%sugar= 1.1586% ≅ 1.16 %

Thus, the percent composition of sugar is 1.16%. Hence, option E is correct.

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Answer:

option b

Explanation: