3. Calculate the answers to the appropriate number of significant figures. e) 43.678 x 64.1 = f) 1.678/0.42 =

Answer:

história phkfk

Explanation:

guiooupigjdytrss

Answer:

D.) ±0.01 cm?​

Explanation:

Since 32.23 cm has two decimal places, the uncertainty is taken as one-half the last decimal pace.

The last decimal place is 0.03. Half of this is 0.03 cm/2 = 0.015 cm.

Since we cannot go below two decimal places, we ignore the 5 in 0.015 cm.

So, we have our uncertainty as 0.01 cm.

So, the best expression of the uncertainty in the measurement 32.23 cm is ± 0.01 cm.

So, the answer is D. which is ± 0.01 cm.

Answer:

e. 0.175

Explanation:

The equilibrium constant of a reaction is the value of its reaction quotient when at equilibrium. The equilibrium concentration of a product or reactant depends on the initial concentrations and equilibrium constant of the reactants and products.

The weak acid approximation depends on the initial concentration and equilibrium constant ([tex]K_a[/tex]). The farther the initial concentration and equilibrium constant are from one another, the more likely the approximation would be valid.

Answer:

See explanation

Explanation:

According to the valence shell electron pair repulsion theory, the shape of a molecule depends on the number of electron pairs on the valence shell of the central atom in the molecule.

So, in order to identify the electron domain geometry of a molecule (number of regions of electron density)

1) draw the full Lewis structure of the molecule/ion

2) indicate the electron pairs surrounding the central atom

3) count the number of electron pairs surrounding the central atom

4) decide on the electron pair geometry using valence shell electron pair repulsion theory.

In this exercise we have to use our knowledge of electrons to describe our molecular formula, so we have to:

The valence shell is the outermost shell that an atom can present, that is, it is the shell furthest from the nucleus of an atom.

Electrons are negatively charged particles that revolve around the atomic nucleus and have a mass 1836 times less than that of protons and neutrons. Electrons are particles that are part of the constitution of the atom.

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Explanation:

strong electrolyte- Nacl HCL NAOH

weak electrolyte- c12H22O, NH3

NaCl,HCl and NaOH  are strong electrolytes while ammonia is a weak electrolyte and sucrose is a non-electrolyte.

It is a solution which consists of ions which are electrically conducting as a result of movement of ions.Class of electrolytes include most soluble salts,acids and bases which are dissolved in a polar solvent.On dissolution, they separate into the constituent ions.

There are 3 classes according to the nature of substance which results upon dissolution:

1) Strong electrolytes- Substances which on dissolution in a medium dissociate completely are strong electrolytes. eg: NaCl,HCl

2) Weak electrolytes-  Substances which on dissolution in a medium dissociate partially are weak electrolytes. eg: NH₃

3)Non-electrolytes- Substances which do not dissociate on dissolution are non-electrolytes. eg: sucrose

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Answer:

See explanation

Explanation:

If we look at the question closely, we will notice that the metal in question must be aluminum.

When aluminum is treated with sodium hydroxide, a precipitate, aluminium hydroxide is formed as follows;

Al(s) + 3NaOH(aq) ---> Al(OH)3(s) + 3Na(s)

In excess sodium hydroxide, the precipitate dissolves as follows;

Al(OH)3(s) + NaOH(aq) ----> [NaAlOH4]^-(aq)

The complex formed is sodium aluminum tetrahydroxo aluminate III.

The reaction of aluminum faith dilute hydrochloric acid occurs as follows to yield aluminum chloride;

2Al(s) + 6HCl(aq) ----> 2AlCl3(aq) + 3H2(g)

When aluminum metal is heated strongly, it yields aluminum oxide;

2Al(s) + 3O2(g) ---> Al2O3(s)

Answer:

Option E

Explanation:

From the question we are told that:

Amount of sand in percentage [tex]s_p=45%[/tex]

Sample size[tex]n=120g[/tex]

Note:After being dumped in the river repeatedly the sugar melts away leaving behind the insoluble sand

Generally the equation for Amount of sand content is mathematically given by

 [tex]X=n*s_p[/tex]

 [tex]X=120*\frac{45}{100}[/tex]

 [tex]X=54g[/tex]

Therefore

After drying, the mass of the contents of the bag equals

 [tex]X=54g[/tex]

Option E

Answer:

D

Explanation:

D

The mode of decay for each of the following unstable nuclides are (a) ⁵⁷Ti is beta decay (b) ⁵⁹Zn is Positron emission (c) ¹²³Ba is Positron emission (d) ⁶⁰Cr is beta decay.

Now lets predict the mode of decay for each of the following:

(a) Ti - 57

⁵⁷Ti₂₂ → ⁵⁷V₂₃  + ⁰e₋₁

Here A is unchanged and Z is increases by 1 so the mode of decay is beta decay.

(b) Zn - 59

⁵⁹Zn₃₀ → ⁵⁹Cu₂₉ + ⁰e₊₁

Here A is unchanged and Z is decreases by 1 so the mode of decay is Positron emission.

(c) Ba - 123

¹²³Ba₅₆ → ¹²³Cs₅₅ + ⁰e₊₁

Here A is unchanged and Z is decreases by 1 so the mode of decay is Positron emission.

(d) Cr -60

⁶⁰Cr₂₄ → ⁶⁰Mn₂₅ + ⁰e₋₁

Here A is unchanged and Z is increases by 1 so the mode of decay is beta decay.

Thus, from above conclusion  we can say that (a) ⁵⁷Ti is beta decay (b) ⁵⁹Zn is Positron emission (c) ¹²³Ba is Positron emission (d) ⁶⁰Cr is beta decay.

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Answer:

my define it will be turst me is c

Answer:

0050 hours

Explanation:

The size of the drops is regulated by types of tubing in microdrip tubing 1cc(1ml ) forms 60 gtt.

Gtt in 500 cc D5W is 500×60 gtt.= 30000 gtt.

Time required to infuse whole fluid with the rate of 60gtt /min = 30000gtt÷60gtt/min = 500minute.

= 8hours 20 minute.

Fluid infusion started at 1630 hours after and it ends after 8 hours 30 minutes .

Therefore, infusion will be completed at 1630 hours +0830 hours.= 0050 hours.

Answer:

Clay soil

Explanation:

We were told in the question about two samples of soil A and B. Sample B was confirmed to be loamy soil but it was discovered that sample A absorbed more water than sample B.

We now have to think about the kind of soil that has the greatest ability to absorb water. That soil type is called clay soil.

Clay soils possess a large surface area which is responsible for its ability to absorb more water. Hence, clay soil has the greatest water holding capacity.

Answer:

• 1 kilocaloric equals 1000 gram calories

• 1 kilocalorie is equals to 4184 Joules of energy.

Explanation:

One kilocalorie is equals to 1000 gram calories because one kilo is equals to or have 1000 grams. One kilocalorie is equals to 4184 Joules of energy while on the other hand, one calorie is equals to 4.184 Joules of energy because one calorie is 1000 times smaller than Kilocalorie so calorie has also 1000 times lower energy than kilocalorie. Kilo is the prefix which means 1000 so we can say that One kilocalorie is equals to 1000 gram calories.

Answer:

It is A, The daughter product has the wrong atomic number

Explanation:

Have trust, please i beg of you.

:) thank me later, love ya

The daughter's product has the wrong atomic number. Hence, option A is correct.

Nuclear equations represent the reactants and products in radioactive decay, nuclear fission, or nuclear fusion.

Beta decay - A common mode of radioactive decay in which a nucleus emits beta particles. The daughter nucleus will have a higher atomic number than the original nucleus.

Hence, the daughter's product has the wrong atomic number.

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Answer:

For the neutralization reaction between pyridine and propanoic acid, draw curved arrows to indicate the direction of electron flow.

Draw curved arrows to show the movement of electrons in this step of the mechanism.

Explanation:

According to Bronsted acid-base theory, an acid is a substance which is a proton donor.

Base is the proton acceptor.

In the given example, acid is propanoic acid and it loses the proton.

Pyridine is the base and it accepts the proton from propanoic acid.

The entire reaction is shown below:

Answer:

[tex]m_{HCl}=36.1gHCl[/tex]

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to calculate the required grams of HCl by firstly identifying the limiting reactant via the moles of each reactant as they are in a 1:1 mole ratio:

[tex]n_{H_2}=1.00gH_2*\frac{1molH_2}{2.02gH_2}=0.500molH_2\\\\ n_{Cl_2}=55.0gCl_2*\frac{1molCl_2}{70.9gCl_2}=0.776molCl_2[/tex]

Thus, we infer the hydrogen is the limiting reactant and therefore we use its 1:2 mole ratio with HCl whose molar mass is 36.46 g/mol:

[tex]m_{HCl}=0.500molH_2*\frac{2molHCl}{1molH_2}*\frac{36.46gHCl}{1molHCl}\\\\m_{HCl}=36.1gHCl[/tex]

Regards!

Answer:

Compare the solubility of silver chloride in each of the following aqueous solutions:

a. 0.10 M AgNO3 More soluble than in pure water.

b. 0.10 M NaCI Similar solubility as in pure water

c. 0.10 M KNO3 Less soluble than in pure water.

d. 0.10 M NH4CH3COO

Explanation:

This is based on common ion effect.

According to common ion effect, the solubility of a sparingly soluble salt decreases in a solution containing common ion to it.

The solubility of AgCl(s) is shown below:

[tex]AgCl(s) <=> Ag^{+}(aq)+Cl^-(aq)[/tex]

So, when it is placed in:

a. 0.10 M AgNO3

Due to common ion effect Ag+, its solubility is less in this solution than in pure water.

b. 0.10 M NaCI :

Due to common ion effect Cl-, its solubility is less in this solution than in pure water.

c. 0.10 M KNO3 :

In this solution there is no presence of common ion.

So, the solubility of AgCl in this solution is similar to that of pure water.

d. 0.10 M NH4CH3COO:

In this solution, AgCl forms a precipitate.

So, the solubility of AgCl is more in this solution compared to pure water.

Answer: The mass of Cu produced is 4.88 g

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass.

The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of aluminum = 2.98 g

Molar mass of aluminum = 27 g/mol

Plugging values in equation 1:

[tex]\text{Moles of aluminum}=\frac{2.98g}{27g/mol}=0.1104 mol[/tex]

The given chemical equation follows:

[tex]2Al(s)+3CuSO_4(aq)\rightarrow Al_2(SO_4)_3(aq)+3Cu(s)[/tex]

By the stoichiometry of the reaction:

If 2 moles of aluminum produces 3 moles of Cu

So, 0.1104 moles aluminium will produce = [tex]\frac{3}{2}\times 0.1104=0.1656mol[/tex] of Cu

Molar mass of Cu = 63.5 g/mol

Plugging values in equation 1:

[tex]\text{Mass of Cu}=(0.1656mol\times 63.5g/mol)=10.516g[/tex]

The percent yield of a reaction is calculated by using an equation:

[tex]\% \text{yield}=\frac{\text{Actual value}}{\text{Theoretical value}}\times 100[/tex] ......(2)

Given values:

% yield of product = 46.4 %

Theoretical value of the product = 10.516 g

Plugging values in equation 2, we get:

[tex]46.4=\frac{\text{Actual value of Cu}}{10.516g}\times 100\\\\\text{Actual value of Cu}=\frac{46.4\times 10.516}{100}\\\\\text{Actual value of Cu}=4.88g[/tex]

Hence, the mass of Cu produced is 4.88 g

Answer:

That means Cu2O is limiting reagent and C is excess reagent

Explanation:

Based on the reaction, 1 mole of Cu2O reacts per mole of C. The ratio of reaction is 1:1.

To solve this question we need to convert the mass of each reactant to moles. The reactant with the lower amount of moles is limiting reactant and the excess reactant is the reactant with the higher number of moles.

Moles Cu2O -Molar mass: 143.09 g/mol-

114.2g Cu2O * (1mol / 143.09g) = 0.798 moles Cu2O

Moles C -Molar mass: 12.01g/mol-

11.1g C * (1mol / 12.01g) = 0.924 moles C

Explanation:

the answer is in the image above

Answer:

A physical change is a change in form.

A Chemical change is a change in materials.

Explanation:

Example of a physical change would be an ice cube meting.

Example of a chemical change would be mixing food coloring into a cup of water.

Answer:

0.51

Explanation:

Given the Nernst equation;

E= E° - 0.0592/n logQ

E= 355 mV or 0.355 V

E° = 0.34 - 0= 0.34 V

n= 2(two electrons were transferred in the process)

Equation of the reaction;

H2(g) + Cu^2+(aq) -----> 2H^+(aq) + Cu(s)

Substituting values;

0.355 = 0.34 - 0.0592/2 log([H^+]/1)

0.355 - 0.34 = - 0.0296 log [H^+]

0.015/-0.0296 = log [H^+]

Antilog (-0.5068) = [H^+]

[H^+] = 0.311 M

pH = -log[H^+]

pH= - log(0.311 M)

pH = 0.51

The potential difference between the half cell of the electrochemical cell is called cell potential. The pH of the solution at 355 mV will be 0.51.

An electrochemical cell generates electricity from the redox chemical reactions occurring inside the cell.

The balanced chemical reaction is shown as,

[tex]\rm H_{2}(g) + Cu^{2+}(aq) \rightarrow 2H^{+}(aq) + Cu(s)[/tex]

Using the Nernst equation:

[tex]\rm E= E^{\circ} - \dfrac{0.0592}{n }logQ[/tex]

Given,

E = 0.355 V

E° = 0.34 V

n = 2

Substituting values in the above equation:

[tex]\begin{aligned} 0.355 &= 0.34 - \dfrac{0.0592}{2} \;\rm log(\dfrac{[H^{+}]}{1})\\\\0.355 - 0.34 &= - 0.0296 \rm \; log [H^{+}]\\\\\dfrac{0.015}{-0.0296} &= \rm \; log [H^{+}]\end{aligned}[/tex]

Solving further,

[tex]\begin{aligned} \rm Antilog (-0.5068)& = \rm [H^{+}]\\\\\rm [H^{+}] &= 0.311 \;\rm M \end{aligned}[/tex]

The pH of the solution is calculated as:

[tex]\begin{aligned} \rm pH &= \rm -log[H^{+}]\\\\&= \rm - log(0.311\; M)\\\\&= 0.51\end{aligned}[/tex]

Therefore, 0.51 is the pH of the solution.

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Answer:

3Ca²⁺(aq) +  2PO4³⁻(aq) → Ca3(PO4)2(s)

Explanation:

The calcium of CaCl2 reacts with the phosphate ion od Cs3PO4 to produce the insoluble salt Ca3(PO4)2 and CsCl. The unbalanced reaction is:

CaCl2(aq) + Cs3PO4(aq) → Ca3(PO4)2(s) + CsCl(aq)

To balance the calciums:

3CaCl2(aq) + Cs3PO4(aq) → Ca3(PO4)2(s) + CsCl(aq)

The chlorides:

3CaCl2(aq) + Cs3PO4(aq) → Ca3(PO4)2(s) + 6CsCl(aq)

And the Cs:

3CaCl2(aq) + 2Cs3PO4(aq) → Ca3(PO4)2(s) + 6CsCl(aq)

This is the balanced reaction, the ionic equation is:

3Ca²⁺(aq) + 6Cl⁻(aq) + 6Cs⁺(aq) + 2PO4³⁻(aq) → Ca3(PO4)2(s) + 6Cs⁺(aq) + 6Cl⁻(aq)

Subtracting the ions that don't react:

This is the net ionic equation

The balanced, net ionic equation for the precipitation reaction of CaCl₂ and Cs₃PO₄ in an aqueous solution can be written as follows:

3Ca²⁺(aq) + 2PO₄³⁻(aq) -> Ca₃(PO₄)₂(s)

A balanced equation is a chemical equation in which the number of atoms of each element on both sides of the equation is equal. It follows the law of conservation of mass, which states that matter cannot be created or destroyed in a chemical reaction.

In a balanced equation, the coefficients in front of each compound or molecule indicate the number of moles or molecules involved in the reaction. By adjusting these coefficients, the equation is balanced in terms of both mass and charge.

In this equation, Ca²⁺ ions from calcium chloride (CaCl₂) combine with PO₄³⁻ ions from cesium phosphate (Cs₃PO₄) to form solid calcium phosphate (Ca₃(PO₄)₂). The net ionic equation represents only the species directly involved in the reaction and excludes spectator ions, which do not participate in the formation of the precipitate. The physical states are denoted as (aq) for aqueous and (s) for solid.

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Answer:

Which type of chemistry studies the chemical reactions that occur in the human body? .

biochemistry

The correct answer is biochemistry.

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Answer:

iv. N³⁻, O²⁻, F⁻, Na⁺, Mg²⁺

Explanation:

Isoelectronic elements are those that have the same number of electrons. So, if at least 2 elements differ in their number of electrons, the series is not of isoelectronic elements.

To know the number of electrons we will consider the atomic number and add electrons if it is an anion and subtract electrons it is a cation.

Identify the isoelectronic elements.

Answer:

The mixture is not in equilibrium, the reaction will shift to the left.

Explanation:

Based on the equilibrium:

Fe³⁺+ HSCN ⇄ FeSCN²⁺ + H⁺

kc = 30 = [FeSCN²⁺] [H⁺] / [Fe³⁺] [HSCN]

Where [] are concentrations at equilibrium. The reaction is in equilibrium when  the ratio of concentrations = kc

Q is the same expression than kc but with [] that are not in equilibrium

Replacing:

Q = [10.0M] [1.0M] / [0.1M] [0.1M]

Q = 1000

As Q > kc, the reaction will shift to the left in order to produce Fe³⁺ and HSCN untill Q = Kc

Answer: The value of [tex][H_{3}O^{+}][/tex] is [tex]6.025 \times 10^{-12}[/tex] M and [tex][OH^{-}][/tex] is [tex]1 \times 10^{-14}[/tex].

Explanation:

pH is the negative logarithm of concentration of hydrogen ion.

It is given that pH is 11.22. So, the value of concentration of hydrogen ions is calculated as follows.

[tex]pH = - log [H^{+}]\\11.22 = - log [H^{+}]\\conc. H^{+} = 6.025 \times 10^{-12}[/tex] M

Let the value [tex]6.025 \times 10^{-12}[/tex] is considered as equal to 0. Hence, the relation between pH and pOH value is as follows.

pH + pOH = 14

0 + pOH = 14

pOH = 14

Now, pOH is the negative logarithm of concentration of hydroxide ions.

Hence, [tex][OH^{-}][/tex] is calculated as follows.

[tex]pOH = - log [OH^{-}]\\14 = - log [OH^{-}]\\conc. OH^{-} = 1 \times 10^{-14} M[/tex]

Thus, we can conclude that the value of [tex][H_{3}O^{+}][/tex] is [tex]6.025 \times 10^{-12}[/tex] M and [tex][OH^{-}][/tex] is [tex]1 \times 10^{-14}[/tex].

Answer:

Some bacteria like rhizobium and blue green algae are able to fix nitrogen gas from the atmosphere to enrich the soil with nitrogen compounds and increase its fertility. The nitrogen-fixing bacteria and blue green algae are called biological nitrogen fixers.

Answer:

Diazotrophic bacteria or Cyanobacteria

Answer:

∵

Explanation: