Engineers come up with as many ideas to solve a problem as possible is so as to choose the best which is applicable in helping people.
Who is an Engineer?This is referred to as an individual or a professional which employs the use of scientific knowledge in the construction and building of different types of machines and tools.
An engineer is someone who has a good analytic and problem solving skills and comes up with many ideas so as to be able to choose the best from the set of alternatives in helping people solve their problems or issues.
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I'm a little confused as to what this question is asking of me. (This is a test review question because I have a test soon)
This question asks you to get 5 of Dalton's postulates and analyze them based on current knowledge.
For example, imagine a postulate saying that atoms are indivisible. Based on what is known nowadays, you may agree with the postulate and keep it as it is; or disagree with this postulate and discard it or modify it. Since we already know that atoms are divided into sub-particles such as protons, neutrons, and electrons, this would be the modification for this postulate, in this example.
Besides that, the question suggests that you make a table with 3 columns, being the first one the postulate itself, then the second could be if you would keep, modify or discard; and the third could be the modification if that was the case.
If the reaction in the given equation produced 0.364 moles of H2 gas at STP, how many liters would this amount of H2 occupy? [hint - the H2 gas is at STP! Is there a special conversion we can use?]
Equation: 6 HCl + 2 Al ---> 2 AlCl3 + 3 H2
In the given equation produced 0.364 moles of H₂ gas at STP, 22.4 liters volume would this amount of H₂ occupy.
What is moles?The mole, denoted by the sign "mol," is the volume of a system that has the same number of atoms in 0.012 kilograms of carbon-12 as there are elementary particles.
The equation becomes:
6 HCl + 2 Al → 2 AlCl₃ + 3 H₂
6 mol 2 mol 2 mol 3 mol
As we know,
one mole of a gas occupies 22.4 liters.
Here, in the above equation, 3 moles of H₂ gas is produced.
So, in STP condition 3 moles of H₂ gas occupy = 3 × 22.4 lit
= 67.2 lit
Thus, in the given equation produced 0.364 moles of H₂ gas at STP, 22.4 liters volume would this amount of H₂ occupy.
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4 Si + S8 --> 2 Si2S4
We usually represent a synthesis like this:
A + B ------> AB
So, when looking at our equation, it is really similar to it
4 Si + S8 ----> 2 Si2S4
We are combining two compounds to get a different one
A buret dispenses 16.4 mL of a 0.521 M NaOH solution. How many moles of NaOH were dispensed?
The number of moles will be 8.54 mole.
The concentration can be expressed as the ratio of number of mole and volume . It can be shown as:
C= n/V
where, C is concentration, n is number of moles and V is volume.
The given data:
C = 0.521 M
V = 16.4 mL
n = ?
The number of moles can be determined by using the formula:
C = n/v
n = C×v....(i)
Put the values of given data in above equation.
n = 0.521 × 16.4
n = 8.54
Therefore, the number of moles will be 8.54 mole.
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Convert 8.81 x 10^-3m to nm
Answer:
8.81 x 10⁶ nm.
Explanation:
Remember that 1 m (meter) equals 1 x 10⁹ nm (nanometer), so if we state a rule of three based on this information and the given data:
[tex]\begin{gathered} 1\text{ m }\Rightarrow1\cdot10^9nm \\ 8.81\cdot10^{-3}m\Rightarrow?\text{ nm.} \end{gathered}[/tex]The calculation will look like this:
[tex]8.81\cdot10^{-3}\text{ m}\cdot\frac{1\cdot10^9\text{ nm}}{1\text{ m}}=8.81\cdot10^6\text{ nm.}[/tex]The answer would be that 8.81 x 10⁻³ m equals 8.81 x 10⁶ nm.
If 129.63grams of aluminum metal is reacted with767.44grams of iron (III) oxide, what mass ofaluminum oxide is likely to form?Reaction: 2Al(s) + Fe2O3(aq)--> Al2O3(aq) + 2Fe(s)
Step 1
The reaction must be written, completed, and balanced:
2Al(s) + Fe2O3(aq) => Al2O3(aq) + 2Fe(s)
----------------------
Step 2
Information provided:
The mass of Al = 129.63 g
The mass of Fe2O3 = 767.44 g
(because of this, the limiting reactant must be determined)
---
Information needed:
The molar masses:
Al) 26.981 g/mol
Fe2O3) 159.69 g/mol
---------------------
Step 3
The limiting reactant:
2Al(s) + Fe2O3(aq) => Al2O3(aq) + 2Fe(s)
By stoichiometry => 1 mole Al = 26.981 g and 1 mole Fe2O3 = 159.69 g
Procedure:
2 x 26.981 g Al --------- 159.69 g Fe2O3
129.63 g Al ---------- X
X = 129.63 g Al x 159.69 g Fe2O3/2 x 26.981 g Al = 383.61 g
(For 129.63 g of Al, 383.61 g of Fe2O3 is needed, but there is 767.44 g of Fe2O3. Therefore, the limiting reactant is the Al and the excess is the Fe2O3)
-----------------------
Step 4
The mass of Al2O3: (molar mass of Al2O3 = 101.96 g/mol)
2Al(s) + Fe2O3(aq) => Al2O3(aq) + 2Fe(s)
2 x 26.981 g Al ------- 101.96 g Al2O3
129.63 g Al ------- X = 244.93 g
Answer: mass of aluminum oxide = 244.93 g
How much water must be added to 560 mL of 15M H2SO4 solution to prepare a 3.0M solution?
Answer
The volume of water that must be added = 2240 mL
Explanation
Given:
Initial concentration, C₁ = 15 M
Initial volume of solution, V₁ = 560 mL
Final concentration, C₂ = 3.0 M
What to find:
The volume of water added to 560 mL of 15M H2SO4 solution to prepare a 3.0M solution.
Step-by-step solution:
The solution involves two steps.
Step 1: Calculate the final volume, V₂ of the solution using the dilution formula.
[tex]\begin{gathered} C_1V_1=C_2V_2 \\ \\ 15\text{ }M\times560\text{ }mL=3.0\text{ }M\times V_2 \\ \\ V_2=\frac{15\text{ }M\times560\text{ }mL}{3.0\text{ }M} \\ \\ V_2=\frac{8400\text{ }mL}{3.0} \\ \\ V_2=2800\text{ }mL \end{gathered}[/tex]Step 2: Subtract the initial volume of the solution from the final volume in step 1 to determine the amount of water added.
The volume of water that must be added = V₂ - V₁
The volume of water that must be added = 2800 mL - 560 mL = 2240 mL
Complete the first row of the table.Express the volume in liters to three significant figures.
Answer:
[tex]V_2\text{ = 149 L}[/tex]Explanation:
Here, we want to get the missing volume
From Charles' law, we know that volume and temperature are directly proportional at constant pressure
Mathematically, we know that:
[tex]\frac{V_1}{T_1}=\frac{V_2}{T_2}_{}[/tex]We have to rewrite the formula in terms of the missing value as follows:
[tex]V_2\text{ = }\frac{V_1T_2}{T_1}[/tex]Before we proceed to input the values, we have to convert the temperatures in celsius to kelvin by adding 273.15 K to the celsius temperature
Thus, we have it that:
[tex]\begin{gathered} V_1\text{ = 112L} \\ V_2\text{ = ?} \\ T_1\text{ = 10.2 + 273.15 = 283.35 K} \\ T_2\text{ = 106.1 + 273.15 = 379.25 K} \end{gathered}[/tex]We can now proceed to substitute these values into the rewritten formula as follows:
[tex]V_2\text{ = }\frac{112\times379.25}{283.35}\text{ = 149 L}[/tex]calculate the mass solute and the mass solution when the mass solvent is 315.2g and the mass percent is 15.3 %.
Answer
mass of solute = 48.2 g
Mass of solution = 363.4 g
Explanation
Given:
Mass of solvent = 315.2 g
mass percentage = 15.3 %
Required
mass of the solute
mass of the solution
Solution:
mass % = mass of solute/mass of solvent
15.3/100 = mass of solute/315.2 g
0.153 = mass of solute/315.2 g
mass of solute = 0.153 x 315.2
mass of solute = 48.2 g
Mass of solution = mass of solute + mass of solvent
Mass of solution = 48.2 g + 315.2 g
Mass of solution = 363.4 g
Calculate the [OH−] of each aqueous solution with the following [H3O+].baking soda, 1.7×10−8M
Answer:
The [OH−] is 5.88x10^-7M.
Explanation:
1st) It is necessary to calculate the pH of the solution using the pH formula and replacing the concentration of H3O+:
[tex]\begin{gathered} pH=-log\left[H_3O+\right] \\ pH=-log(1.7×10−8) \\ pH=7.77 \end{gathered}[/tex]Now we know that the pH is 7.77.
2nd) Now we can calculate the pOH of the solution using the relation between pH and pOH:
[tex]\begin{gathered} pH+pOH=14 \\ 7.77+pOH=14 \\ pOH=14-7.77 \\ pOH=6.23 \end{gathered}[/tex]Now we know that the pOH of the solution is 6.23.
3rd) Finally, we can calculate the [OH−] using the pOH formula and replacing the value of pOH:
[tex]\begin{gathered} pOH=-log\left[OH−\right] \\ 6.23=-log\left[OH−\right] \\ 10^{(-6.23)}=\left[OH−\right] \\ 5.88*10^{-7}=\left[OH−\right] \end{gathered}[/tex]So, the [OH−] is 5.88x10^-7M.
The universal indicator changes color throughout the pH range. How is this indicator produced?
Answer and Explanation:
The color change of a pH indicator is caused due to the dissociation of protons H+. The most common indicators are: phenolphthalein, methyl red, and bromothymol blue, which are used to indicate pH ranges of about 8 to 10, 4.5 to 6, and 6 to 7.5, respectively. For each indicator, phenolphthalein goes from colorless to pink, methyl red goes from red to yellow, and bromothymol blue goes from yellow to blue.
Calculate the mass in grams of CO2 in 45.0 L of CO2 at STP
One of the options in the question is 22.4 L, which is the value for the volume of 1mol of gas in the old STP definition. Since there is no option for the updated STP conditions, we will need to assume it want in this old one.
In the old STP conditions, 1 mol of gas occupies 22.4 L, so we can use the rule of three to calculate how many moles are in 45.0L:
22.4L --- 1mol
45.0L --- n
[tex]\begin{gathered} \frac{22.4L}{45.0L}=\frac{1mol}{n} \\ n=45.0L\times\frac{1mol}{22.4L} \end{gathered}[/tex]Now, we want to convert to mass. Consulting the molar mass of CO₂, we can see that it is approximately 44.01g/mol, which is one of the optios. That is, in 1 mol of CO₂ there are 44.01 g. Using the rule of three:
1 mol --- 44.01 g
n --- m
[tex]\begin{gathered} \frac{1mol}{n}=\frac{44.01g}{m} \\ m=n\times\frac{44.01g}{1mol} \end{gathered}[/tex]Inputting the n we calculated earlier, we have:
[tex]m=45.0L\times\frac{1mol}{22.4L}\times\frac{44.01g}{1mol}\approx88.4g[/tex]So, there is approximately 88.4g of CO₂.
Use a diagram to illustrate how a carbon-carbon double bond forms.
Carbon forms a double bond with another carbon by sharing two pairs of electrons.
The electron dot diagram of the carbon double bond is illustrated in the figure below.
Draw the electron dot diagram for H2CO and determine how many bonded pairs of electrons there are.
Pleasseeeeeee
The electron dot diagram is shown in the image attached to this answer.
What is the electron dot diagram?We know that an electron dot diagram is used to show the electron pairs that are present in a compound. the electron dot diagram would include the symbols of the elements as well as the number of electron pairs that can be found on the valence shells of each of the atoms.
In this case, we can see that the electrons that are involved in a bod are shown as a single dash where the dash shows the electrons that are involved in a covalent bonding situation.
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Find the oxidation numbersi) Oxidation number of Pb in PbOj) Oxidation number of O in PbOk) Oxidation number of Pb in PbO2l) Oxidation number of O in PbO2
Answer:
i) The oxidation number of Pb in PbO is +2.
j) The oxidation number of O in PbO is -2.
k) The oxidation number of Pb in PbO2 is +4.
l) The oxidation number of O in PbO2 is -2.
Explanation:
j) We can start from Oxygen since its oxidation number is alway -2 (except in peroxides where it is -1).
i) As we can see the molecule of PbO is neutral, so knowing that Oxygen has an oxidation number of -2, Pb will have an oxidation number of +2 to make the molecule neutral.
l) We can also start with oxygen for PbO2 molecule, as the same in PbO, O has an oxidation number of -2.
k) PbO2 is also a neutral molecule, but in this case, there are 2 Oxygens with oxidation number of -2, so the total negative charge is -4 ((-2)*2), so to make the whole molecule neutral, Pb must have an oxidation number of +4.
What would the products of a double-replacement reaction between NaF andMgS be? (Remember: In double-replacement reactions, the two cationsswitch places and the two anions switch places.)O A. NaF and MgsB. MgF and NashO C. F2S and MgNa2O D. MgF2 and Na2SSUBMIT
Step 1
The reaction between NaF and MgS:
2NaF + MgS => Na2S + MgF2
(Remember: In double-replacement reactions, the two cations switch places and the two anions switch places.)
Answer: D. MgF2 and Na2S
Which statement best decribes the law of
conservation of mass?
d. The mass of the reactants and products is equal and is not dependent on the physical state of the substances explains the correct statement about the law of conservation of mass.
The law of conservation of mass is the law that states that matter or energy can neither be created nor destroyed. This means that the amount of matter in the universe is always the same. The law of conservation of mass is a fundamental law of physics and it is always obeyed by all physical processes.
The amount of matter in a closed system (one that is not subject to outside influences) will remain constant over time.
It is always obeyed even under the most extreme conditions, such as during nuclear reactions.
Hence, the correct option is d.
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6. What number uniquely identifies an element?
Answer:
atomic number
Explanation:
"The atomic number uniquely identifies a chemical element. It is identical to the charge number of the nucleus. In an uncharged atom, the atomic number is also equal to the number of electrons."
Please help me find the final answer for number six
1.28x10^23 molecules of carbon dioxide are expelled.
1st) It is necessary to write the balanced equation of combustion from sugar:
[tex]C_{12}H_{22}O_{11}+12O_2\text{ }\rightarrow12CO_2+11H_2O[/tex]2nd) We need to look for the molar mass of C12H22O11 and CO2 to make a relation between those values:
- C12H22O11 molar mass: 342 g/mol
- CO2 molar mass: 44 g/mol
3rd) According to the balanced chemical equation, 1 mol of C12H22O11 produces 12 moles of CO2. Using the molar mass of the compound, in grams, 342g of C12H22O11 produces 528 g (44gx12) of CO2.
Now, with a mathematical Rule of Three we can find the amount of CO2 that is produced from 6.06g of C12H22O11:
[tex]\begin{gathered} 342gC_{12}H_{22}O_{11}-528gCO_2 \\ 6.06gC_{12}H_{22}O_{11}-x=\frac{6.06g\cdot528g}{342g} \\ x=9.36gCO_2 \end{gathered}[/tex]4th) Knowing that 6.06g of jolly rancher produces 9.36g of carbon dioxide, and using the Avogadro's number (6.022x10^23 molecules/mol), we can find the molecules of CO2:
[tex]\begin{gathered} 44gCO_2-6.022\cdot10^{23}molecules \\ 9.36gCO_2-x=\frac{9.36gCO_2\cdot6.022\cdot10^{23}molecules}{44gCO_2} \\ x=1.28\cdot10^{23}molecules \end{gathered}[/tex]So, 1.28x10^23 molecules of carbon dioxide are expelled from the combustion of one jolly rancher.
We can write it in just one equation like this:
[tex]6.06g\cdot\frac{528g}{342g}\cdot\frac{6.022\cdot10^{23}\text{molecules}}{44g}=1.28\cdot10^{23}molecules[/tex]And the result will be the same.
In a good scientific experiment, the dependent variable depends on the…Select oneA. Experimental constantsB.independent variableC.experimental errorD.none of these
Answer:
[tex]B:\text{ Independent variable}[/tex]Explanation:
Here, we want to get the variable on which the dependent variable depends on
The dependent variable value is affected by some values which do not depend on other values
These values that are independent of other values are referred to as the independent variable
Given the balanced equation below:3Cu + 8HNO3 — 3Cu(NO3)2 + 2NO + 4H2OThe total number of grams of Cu neededto produce 188 grams of Cu(NO3)2 is?
Answer
Mass of Cu = 63.7 g
Explanation
Given:
A balanced chemical equation: 3Cu + 8HNO3 — 3Cu(NO3)2 + 2NO + 4H2O
Required: The total number of grams of Cu
Solution
[tex]\begin{gathered} 188\text{ g Cu\lparen NO}_3)_2\text{ x }\frac{1\text{ mole Cu\lparen NO}_3)_2}{187,56\text{ g Cu\lparen NO}_3)_2}\text{ x }\frac{3\text{ mole Cu}}{3\text{ mole Cu\lparen NO}_3)_2}\text{ x }\frac{63,546\text{ g Cu}}{1\text{ mole Cu}} \\ \\ =\text{ 63.7 g Cu} \end{gathered}[/tex]If HCl (aq) is added to a saturated NaCl solution the Na+1 will a. Increase b. Decrease c remain the same
For this question, we have a solution with NaCl, and HCl is added to it, even though we have more Cl- in the solution, in terms of equilibrium this will shift the equilibrium to the left, but in terms of quantity of the sodium ion, it will remain the same, since no sodium was added or took away, letter C
A 5.0 L tank contains N2 at a pressure of 214 kPa. The gas is transferred to a second tank, where it’s pressure is measured at 148 kPa. What is the volume of the second tank
The volume of the second tank will be 7.2 L when the pressure is 148 kPa.
Boyle's Rule
Because the gas particles are compressed closer together as the pressure on a gas rises, the volume of the gas decreases. On the other hand, because the gas particles may now move further apart when the pressure on a gas lowers, the gas volume rises.
P 1 * V 1 = P 2 * V 2 can be used to calculate the pressure and volume of a given amount of gas at a fixed temperature.
P*V is a constant.
P stands for gas pressure.
V stands for gas volume.
P2 = 148 kPa
V2 = x
P1 = 214 kPa
V1 = 5.0 L
P1 * V1 = P2 * V2
214 * 5 = 148 * x
x = 7.2 L
V2= 7.2L
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According to the graph above what is the substances melting temperature?
ANSWER
At 90 degrees Celcius the substance will melt completely
EXPLANATION
Melting point is the process in which solid is completely converted to the liquid phase.
In the given graph, the point A the solid particles are closely packed due to strong intermolecular forces binding the particles together. When temperature is applied to the system, the particles of the solid substance vibrate about a point and the particles are said to move independently. Further increase in the temperature will break the bond holding the particles together and turn to liquid at 90 degrees Celcius
Therefore, at 90 degrees Celcius the substance will melt completely and turn to liquid.
The solvent in a collodial system is alsoknown as the [?] phase.ABdispersedparticledispersionmedium
Answer:
[tex]Dispersed\text{ Medium}[/tex]Explanation:
Here, we want to know what the solvent in a colloidal system is called
The solvent is the medium in which we have the solute dissolved
While the solute is called the dispersed phase, the solvent is known as the dispersed medium
How much potential energy does a 20-kg New Year’s Eve ball have at the top of a 100-m-tall pole?
Answer:
First you need velocity. And hight is 10 m. Now the velocity. Let. g = 10m/s. V=mgh. V= 20 . 10. 10. 2000m/s. Now the kinetic energy will be. Ke = 1/2 mv^2.
What is the balanced equation for "magnesium reacts with phosphorus"
Magnesium reacts with Phosphorus and produce Magnesium phosphide. The equation is:
Mg + P ---> Mg₃P₂
The balanced equation is:
3 Mg + 2 P ---> Mg₃P₂
It need to have the same amount of atoms of each element on both sides of the equation.
Answer: 3 Mg + 2 P ---> Mg₃P₂
Hello I’ve been working on this for about an hour and still don’t get it May Someone help? Thank you!
Intensive properties: These are those that do not depend on the mass of the sample.
Density is an intensive property. For example, the density of an ice cube and an iceberg is the same (0.92 g/cm3 at temperatures below 0°C at sea level), which is less than that of water (1.0 g/cm^3 , under a temperature of approximately 4°C and a pressure at sea level, which is equal to 1.0 atm). Therefore, both an ice cube and an iceberg float on water.
2. Extensive properties: These are those that depend on the mass (“extension”) of the sample.
So mass is an extensive property and length as well.
Answer:
Extensive physical properties: mass of 18.45 g and 3.50 cm in length
Intensive physical properties: Density of 2.70 g/cm^3
What is the correct form of the equilibrium constant for the reaction of hydrogen and oxygen to form water? The equation is: 2H 2( g) + O 2( g) ⇌ H 2O( g)
The equilibrium constant is given by the ratio between the products and the reactants, where their stoichiometric numbers are exponents.
[tex]K=\frac{\lbrack H_2O\rbrack^2^{}^{}}{\lbrack H_2\rbrack^2\lbrack O_2\rbrack}[/tex]Observe that the molecule H2O must have a coefficient of 2 in order to balance the equation.
• [H2O] is the equilibrium concentration of the product (water).
,• [H2} is the equilibrium concentration of the hydrogen molecule.
,• [O2] is the equilibrium concentration of the oxygen molecule.
Answer the following question:Reminder R= .0822. If you have 5 moles of a gas at 400 K, what is the pressure if the volume is 15 L?
We are asked to find the pressure of a gas that is in certain conditions. To find it we must assume that there is no interaction between the gas molecules and the gas behaves like an ideal gas, in this way we can apply the ideal gas law that tells us:
[tex]\begin{gathered} PV=nRT \\ P=\frac{nRT}{V} \end{gathered}[/tex]Where,
P is the pressure of the gas
V is the volume of the gas = 15L
T is the temperature of the gas = 400K
n is the number of moles = 5mol
R is a constant = 0.08206 (atm L)//(mol K)
Now, we replace the known data in the equation:
[tex]P=\frac{5mol\times0.08206\frac{atm.L}{mol.K}\times400K}{15L}=11atm[/tex]Answer: The pressure of the gas will be 11 atm