An alkali metal with fewer than 10 protons in its nucleus

Answer:

70.9 grams 3 sig figs

Explanation:

24.1% of 294 grams = 0.241(294 gram) = 70.854 grams ≅ 70.9 grams 3 sig figs

Answer:

Insoluble benzoic acid is formed

Explanation:

When benzoic acid is dissolved in sodium hydroxide solution, sodium benzoate is formed. This compound is highly soluble in the aqueous layer.

If this solution is now acidified, the equilibrum position shifts towards the undissociated benzoic acid and a precipitate appears.

An insoluble substance formed during crystallization or precipitation is called a precipitate. The precipitate of the reaction formed is of benzoic acid.

A precipitation reaction is a type of reaction in which an insoluble salt or substance is formed as the result of the reaction between the soluble salt solutions.

The substance or the salt produced that does not get dissolved in the solution is called a precipitate.

In the reaction, benzoic acid reacts with the sodium hydroxide salt and forms sodium benzoate salt as shown,

[tex]\rm C_{6}H_{5}COOH(s) + NaOH(aq) \rightarrow C_{6}H_{5}COO^{-}Na^{+}(aq) + H_{2}O(l)[/tex]

When the salt of sodium benzoate is acidified then the precipitation of benzoic acid is formed. The precipitate occurs because the equilibrium shifts towards the undissociated benzoic acid.

Therefore, a precipitate of benzoic acid is formed.

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Answer:

1. The pH of 1.0 M trimethyl ammonium (pH = 1.01) is lower than the pH of 0.1 M phenol (5.00).

2. The difference in pH values is 4.95.

Explanation:

1. The pH of a compound can be found using the following equation:

[tex] pH = -log([H_{3}O^{+}]) [/tex]

First, we need to find [H₃O⁺] for trimethyl ammonium and for phenol.

Trimethyl ammonium:

We can calculate [H₃O⁺] using the Ka as follows:

(CH₃)₃NH⁺ + H₂O  →  (CH₃)₃N + H₃O⁺    

1.0 - x                               x           x  

[tex]Ka = \frac{[(CH_{3})_{3}N][H_{3}O^{+}]}{[(CH_{3})_{3}NH^{+}]}[/tex]

[tex] 10^{-pKa} = \frac{x*x}{1.0 - x} [/tex]

[tex] 10^{-9.80}(1.0 - x) - x^{2} = 0 [/tex]    

By solving the above equation for x we have:  

x = 0.097 = [H₃O⁺]

[tex] pH = -log([H_{3}O^{+}]) = -log(0.097) = 1.01 [/tex]                                      

Phenol:

C₆H₅OH + H₂O → C₆H₅O⁻ + H₃O⁺

1.0 - x                        x             x

[tex]Ka = \frac{[C_{6}H_{5}O^{-}][H_{3}O^{+}]}{[C_{6}H_{5}OH]}[/tex]

[tex] 10^{-10} = \frac{x^{2}}{1.0 - x} [/tex]

[tex] 1.0 \cdot 10^{-10}(1.0 - x) - x^{2} = 0 [/tex]

Solving the above equation for x we have:

x = 9.96x10⁻⁶ = [H₃O⁺]

[tex] pH = -log([H_{3}O^{+}]) = -log(9.99 \cdot 10^{-6}) = 5.00 [/tex]

Hence, the pH of 1.0 M trimethyl ammonium is lower than the pH of 0.1 M phenol.

2. The difference in pH values for the two acids is:

[tex] \Delta pH = pH_{C_{6}H_{5}OH} - pH_{(CH_{3})_{3}NH^{+}} = 5.00 - 1.01 = 4.95 [/tex]

Therefore, the difference in pH values is 4.95.

I hope it helps you!

Answer:

A=element

B=compond

C=solution

Answer:

I am sure they are why won't they

Answer:

33

Explanation:

Answer:

you can see the empirical formula at the pic

The empirical formula for compound (a) is NiI2, (b) is BaBr2 and (c) is BeS.

Empirical formula of a compound is defined as the simplest whole number ratio of atoms present in a compound.

(a) 1.245 g Ni : 5.381 g I

Mole of Ni ; Mole of I = 1.245/59 : 5.381/127 = 0.02 : 0.04 = 1:2

So the formula is NiI2

(b) 2.677 g Ba : 3.115 g Br

Mole of Ba : Mole of Br = 2.677/137 : 3.115/60 = 0.019 : 0.038

= 0.02 : 0.04 = 1:2

So the formula is BaBr2

(c) 2.128 g Be : 7.557 g S

Mole of Be : Mole of S = 2.128/9 : 7.557/32 = 0.2 : 0.2 = 1:1

So the formula is BeS

Thus, empirical formula for compound (a) is NiI2, (b) is BaBr2 and (c) is BeS.

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Answer:

B

Explanation:

The front brain(cerebrum) is the part of the brain that controls important cognitive skills in humans, such as emotional expression, problem solving, memory, language, judgment, and sexual behaviors.

Here the students who enjoy acting out plays likely think with front brain. I guess so..

Answer:  The front brain(cerebrum) is the part of the brain that controls important cognitive skills in humans, such as emotional expression, problem solving, memory, language, judgment, and sexual behaviors

Explanation:  people who do acting or choir would use the front brain.....  i think :) hope this helps.

Answer:

LA PRIMERA ES N

Explanation:

Answer : The mole ratio of [tex]PCl_3[/tex] to [tex]PCl_5[/tex] is 1 : 1.

Explanation :

Balanced chemical reaction : It is a chemical reaction in which the number of atoms of individual elements present on reactant side must be equal to the product side.

The balanced chemical reaction is:

[tex]PCl_3+Cl_2\rightarrow PCl_5[/tex]

By the stoichiometry of the reaction we can say that 1 mole of [tex]PCl_3[/tex] reacts with 1 mole of [tex]Cl_2[/tex] to give 1 mole of [tex]PCl_5[/tex].

From this we conclude that the mole ratio of [tex]PCl_3[/tex] to [tex]PCl_5[/tex] is 1 : 1.

Hence, the mole ratio of [tex]PCl_3[/tex] to [tex]PCl_5[/tex] is 1 : 1.

Answer:

A

Explanation:

Answer:

Each nerve cell is connected to the brain by electrical signals

Explanation:

Answer:

they said it above me

Explanation:

Answer:

solute

Explanation:

Hello. You forgot to say that this question is about the possibility of using some type of product that prevents cut apples from becoming darker.

Answer and Explanation:

1. The problem with this activity is "What can you put on an apple slice to keep it from turning brown?" The problem in a scientific experiment is the element that provides a question about what is being observed.

2. Hypotheses are assumptions made about what was observed, in addition, hypotheses can answer the question shown in the problem. In the case of apples, the hypotheses can be: "Lemon juice is the most efficient product in delaying the blackening of cut apples." "Water is inefficient in preventing blackened cut apples." "Milk accelerates the blackness of cut apples."

3. The dependent viable is one that needs to be influenced by another element to bring about a result. In the case of the experiment with apples, the dependent variable is the blackening rate of the apple slices.

4. The independent variable, on the other hand, refers to the element that does not need any influence to cause a result, on the contrary, this variable acts on the dependent variable, influencing it. In the case of this experiment, the independent variable is the types of liquid tested to delay the blackening of cut apples.

5. Lemon was the most efficient liquid. Probably this efficiency is related to the lemon's ability to decrease the strength of antioxidants, due to its very low pH.

Answer:

Explanation:

Here you go!! Hope this helps.

Answer:

homogeneous is consisting a part of or people are similar to each other or are if same type.

Answer:

um wheres thepassage?

Explanation:

Answer:

valence electrons

Explanation:

The valence electrons are the outer most electrons and the principal energy level in which they belong will vary for .

The chemical element which contains four (4) electrons in its third and outer main energy level is: Silicon (Si).

An electron shell can be defined as the outermost shell of an atom of a chemical element around the atomic nucleus.

Hence, an electron shell is an orbital that is typically accompanied by electrons around the nucleus of an atom.

A sublevel is also referred to as an orbital and it can be defined as an energy level that is associated with the electrons found outside the atomic nucleus.

In Chemistry, there are four main (4) types of sublevel and these are:

In the third (3rd) energy level, there are only three (3) sublevels and these are; s, p and d sublevels.

Silicon is a chemical element that is found in group (4) of the periodic table because it has four (4) electrons in its third and outermost shell.  

In its ground state, Silicon (Si) contains the following number of electrons:

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Answer:

[tex]Y=75.6\%[/tex]

Explanation:

Hello.

In this case, since no information about the reacting hydrogen is given, we can assume that it completely react with the 28.0 g of acetylene to yield ethane. In such a way, via the 1:1 mole ratio between acetylene (molar mass = 26 g/mol) and ethane (molar mass = 30 g/mol), we compute the yielded grams, or the theoretical yield of ethane as shown below:

[tex]m_{C_2H_6}^{theoretical}=28.0gC_2H_2*\frac{1molC_2H_2}{26gC_2H_2}*\frac{1molC_2H_6}{1molC_2H_2} *\frac{30gC_2H_6}{1molC_2H_6}\\ \\m_{C_2H_6}^{theoretical}=32.3gC_2H_6[/tex]

Hence, by knowing that the percent yield is computed via the actual yield (24.5 g) over the theoretical yield, we obtain:

[tex]Y=\frac{24.5g}{32.3g}*100\%\\ \\Y=75.6\%[/tex]

Best regards.

Answer:

[a]. 55.5kmol/min.

[b]. The average velocity = 8.3m/s.

pipe diameter = 1.0954m.

Explanation:

So, from the question above we are given the following data or information or parameters which are going to help us in solving the above question;

=> ''A gas stream that contains 1.50 mole% CO2 flows through a pipeline''

=> ''Twenty (20.0) kilograms of CO2 per minute is injected into the line.''

=> '' . A sample of the gas is drawn from a point in the line 150 meters downstream of the injection point and found to contain 2.3 mole% CO2''

=> ''molar gas density is 0.123k mol/m3''

[a].The gas flow rate (k mol/min) upstream of the injection point can be calculated as follows.

- Determine the mass balance= j₁ +[ 20 /.123 × 44] = j₃. Thus, the flow gas rate is given as;

w₁ ×  1.50 mole% CO2 + 3.6954= 2.3 mole% CO2 × w₃.

-3.610 = - 0.008w₁.

w₁ = 451.3 m³/min.

Thus, the flow rate = 0.123 × 451.3 = 55.51 kmol/min.

[b]. The average velocity = 150/ 18 seconds = 8.3 m/s.

[c]. Pipe Diameter can be calculated as follows;

0.123  × 8.3  × [3.12  × (pipe diameter)² / 4] = 55.51/60.

[1.0209  × 3.12]/4  × [pipe diameter]² = 0.9252.

0.8014065  ×  [pipe diameter]² = 0.9252.

[pipe diameter]² = 0.9252/ .8014065.

[pipe diameter]² = 1.15443.

[pipe diameter] = √1.15443.

[pipe diameter] = 1.2 m² = 1.0954m.

A) The gas flow rate (k.mol/min) upstream of the injection point is;

55.51 k.mol/min

B) The average velocity and the diameter of the pipe are respectively;

8.33 m/s and 1.072 m

Due to the fact that there is no reaction or accumulation in the pipeline, we can say that the input of CO₂ is equal to it's output. Thus;

Upstream + Injection = Downstream

A) If we assume that x is the flow rate of gas (kmol/min), then there is the we can write the balance as:

0.015x + (20/44) = 0.023(x + 20/44)

Expanding gives us;

0.015x + 0.4545 = 0.023x + 0.01045

Solving for x gives;

x = 55.51 kmol/min

B) Formula for velocity is;

v = distance/time

Thus, since the length of the pipe is 150 m/s and time is 18 seconds, then velocity is;

v = 150/18

v = 8.33 m/s

Now, volumetric flow rate is calculated from;

Q = q' * ρ

where;

q' is gas flow rate

ρ is gas density

Thus;

Q = 55.51 * 0.123

Q = 451.3 m³/min = 7.522 m³/s

We can also express average velocity as;

v = Q/A

where A is area = πD²/4

Thus;

8.33 = 7.522/(πD²/4)

Making D the subject of the formula gives;

D = √((4 * 7.522)/(8.33π))

D = 1.072 m

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Answer:

true

Explanation:

Condensation is the opposite of vaporization. True. When does condensation occurs, does a gas lose or gain thermal energy?

Answer:

True

Explanation:

Condensation is formed with moisture and cold air, so the removal of thermal energy, or heat, would create the perfect conditions :)

Answer:

chemotherapy

Explanation:

Answer:

[tex]x_{He}=0.975\\x_{O_2}=0.025[/tex]

Explanation:

Hello.

In this case, since we know the mass of both helium and oxygen, in order to obtain the mole fractions we first need the compute the moles by using their atomic masses, 4.00 g/mol and 32.00 g/mol respectively as shown below:

[tex]n_{He}=23.6gHe*\frac{1molHe}{4.00gHe}=5.90molHe\\ \\n_{O_2}=4.85gO_2*\frac{1molO_2}{32.00gO_2}=0.152molO_2\\[/tex]

Therefore, the mole fractions are:

[tex]x_{He}=\frac{n_{He}}{n_{He}+n_{O_2}}=\frac{5.90}{5.90+0.152} \\\\x_{He}=0.975\\\\x_{O_2}=\frac{n_{O_2}}{n_{He}+n_{O_2}} =\frac{0.152}{5.90+0.152} \\\\x_{O_2}=0.025[/tex]

Best regards!

Answer:

true

hope this helps :)

Explanation:

True, [tex]BrF_5[/tex] (aq) is a good insulator.

A material or an object that does not easily allow heat, electricity, light, or sound to pass through it.

Bromine pentafluoride appears as a colourless, fuming liquid with a pungent odour. Used to make other chemicals and in rockets.

Hence,  [tex]BrF_5[/tex] (aq) is a good insulator.

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Answer:

D

Explanation:

trust me bro ive done this

Option D does not represent an example of plants demonstrating the characteristics of life.

The following information should be considered:

Therefore we can conclude that Option D does not represent an example of plants demonstrating the characteristics of life.

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Answer:

molar mass of unknown gas = 1.987 g/mol

Explanation:

First, the number of moles of the unknown gas is found

Using the ideal gas equation: PV = nRT

P = 1.00 atm, V = 5.00 L, T = 298.15 K, R = 0.082 L.atm.mol⁻¹K⁻¹

n = PV/RT

n = (1.00 atm * 5.00 L)/(298.15 K *0.082 L.atm.mol⁻¹K⁻¹)

n = 0.2109 moles

Molar mass = mass/ number of moles

molar mass = 0.419 g/ 0.2109 mols

molar mass of unknown gas = 1.987 g/mol

The molar mass of unknown gas by using ideal gas equation = 1.987 g/mol.

This equation gives the relation between pressure, volume, temperature as given below:

[tex]PV = nRT[/tex]

P = 1.00 atm, V = 5.00 L, T = 298.15 K, R = 0.082 L.atm.mol⁻¹K⁻¹

Substitute the above values in the above equation as follows:

n = (1.00 atm * 5.00 L)/(298.15 K *0.082 L.atm.mol⁻¹K⁻¹)

n = 0.2109 moles

[tex]Molar mass = mass/ number of moles[/tex]

Calculate molar mass by using the above equation,

molar mass = 0.419 g/ 0.2109 moles

The molar mass of unknown gas = 1.987 g/mol

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Answer:

Waves is the disturbance or variation that transfer energy from one location to other

Answer:

this is not in my words but i think this will help

(put some of the words you would use in this)

Explanation:

Transverse waves are always characterized by particle motion being perpendicular to wave motion. A longitudinal wave is a wave in which particles of the medium move in a direction parallel to the direction that the wave moves. ... Longitudinal waves are always characterized by particle motion being parallel to wave motion.

hope i helped

Answer:

CO = 1.320 x 10¹¹ Kg  

NOx = 1.942 x 10¹⁰ Kg

HC = 1.592 x 10¹⁰ Kg  

Explanation:

Given that;

there are approximately 250 million passenger vehicles

each is driven 25,000 km per year which is 15534.28 miles per year

In 1970, the  vehicular emission norms are;

CO = 34 g/mile , NOx = 5 g/mile , HC = 4.1 g/mile

so emission of CO in 1970 is;

250000000 × 15534.28 × 34 g

= 1.320 x 10¹⁴ g

= 1.320 x 10¹¹ Kg  

Also, emission of NOx in 1970

250000000 × 15534.28 × 5 g

= 1.9417 x 10¹³ g

= 1.942 x 10¹⁰ Kg

emission of HC in 1970

= 250000000 × 15534.28 × 4.1 g  

= 1.5922 x 10¹³ g

= 1.592 x 10¹⁰ Kg  

Answer:

1. Faster

Explanation: