Answer:
Yes, given statement is true.
Explanation:
Given that a cylinder of 1000 ml is marked at every 100 ml.
During the test, the student can easily check the volume of liquid so the student's guess is 750 ml true.
With this measurement, we can estimate that 1/10th of 100 ml can be measured.
So, given statement is correct.
Answer:
Yes, the digit in the hundreds place is certain and the digit in the tens place is estimated.
Explanation:
Perform the following calculations and round according to the rules for significant figures. Just type in the number as a number (ex: 44)
8.20cm + 2cm (assume that the number is already labelled with the unit of cm)=
PLEASE HELP
Answer:
10 cm (Approx)
Explanation:
Given:
8.20 cm + 2 cm
Find:
Round of the following number
Computation:
⇒ 8.20 cm + 2 cm
⇒ 10.20 cm
We know that 0.20 < 0.50
So,
⇒ 10.20 cm = 10 cm (Approx)
calculate the number of neutrons in the chlorine 17Cl35 and 17Cl37 ?
Answer: chlorine 17Cl35 has 18 neutrons, and 17Cl37 has 20 neutrons
Explanation: 17 is the atomic number of chlorine which tells us what is the number of protons in chlorine nucleus. 35 and 37 is the mass number of two isotopes of chlorine, it tells us what is the total number of protons and neutrons in atomic nucleus of two chlorine isotopes .
Now to know how many neutrons are in both isotopes we have to substract the number of protons from the mass number of each isotope
For 17Cl35 it will be 35- 17 what makes 18 and for 17 Cl 37 it will be 20 neutrons
A molecule of sugar has 45 atoms to make up the substance. If a sugar crystal has 1000 molecules, how many atoms are present?
Answer:
45000 atoms
Explanation:
a molecule has 45 atoms
1000 molecules have how many atoms??
by mathematical cress cross calculation we get that:
45 X 1000 = 45000 atoms
When determining the standard reduction potential of a substance by using a standard hydrogen electrode as a reference, the standard reduction potential will always be equal to:______.
ta. he reduction potential for the standard hydrogen electrode.
b. one-half the cell potential.
c. the overall cell potential.
d. impossible to predict.
Answer:
the overall cell potential
Explanation:
We must bear in mind that the standard hydrogen electrode is a reference electrode whose electrode potential has been arbitrarily set at 0 V.
The standard hydrogen electrode consists of hydrogen ion solution and hydrogen gas together with a platinum electrode.
The overall cell potential is the reduction potential of the substance being determined using the standard hydrogen electrode as a reference electrode since its electrode potential is set at zero volts.
If salt and water mixed together which is a solvent and which is the solute
Answer:
Solvent = Water
Solute = Salt
Calculate the standard cell potential given the following standard reduction potentials: Al3++3e−→Al;E∘=−1.66 VAl3++3e−→Al;E∘=−1.66 V Ag++e−→Ag;E∘=0.799 V
Answer:
2.459 V
Explanation:
If we look at the data we have from the question closely, we will discover that aluminum has a very negative reduction potential. Recall that very negative reduction potentials are associated with strong reducing agents.
Similarly, silver has a positive reduction potential signifying that it is an oxidizing agent. Since the reducing agent is oxidized in a redox reaction and the oxidizing agent is reduced.
Hence;
E°cell= E°reduction process - E°oxidation process
E°cell= 0.799 -(-1.66)
E°cell= 2.459 V
The standard cell potential is 2.459 V
Standard cell potential:The standard cell potential is the potential difference between the cathode and anode.
The overall cell potential can be calculated by using the equation: [tex]E_0cell=E_0red-E_0oxid[/tex].
Aluminum has a very negative reduction potential. The negative reduction potentials are associated with strong reducing agents and Silver has a positive reduction potential signifying that it is an oxidizing agent. Since the reducing agent is oxidized in a redox reaction and the oxidizing agent is reduced.
Hence;
E°cell= E°reduction process - E°oxidation process
E°cell= 0.799 -(-1.66)
E°cell= 2.459 V
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Consider the following reaction at equilibrium. What effect will increasing the pressure of the reaction mixture have on the system?
CuS(s) + O2(g) ? Cu(s) + SO2(g)
Consider the following reaction at equilibrium. What effect will increasing the pressure of the reaction mixture have on the system?
CuS(s) + O2(g) ? Cu(s) + SO2(g)
a) The equilibrium constant will increase.
b) The reaction will shift to the left in the direction of reactants.
c) The reaction will shift to the right in the direction of products.
d) No effect will be observed.
e) The equilibrium constant will decrease.
Answer:
Choice d. No effect will be observed as long as other factors (temperature, in particular) are unchanged.
Explanation:
The equilibrium constant of a reaction does not depend on the pressure. For this particular reaction, the equilibrium quotient is:
[tex]Q = \displaystyle \frac{[\mathrm{SO_2\, (g)}]}{[\mathrm{O_2\, (g)}]}[/tex].
Note that the two sides of this balanced equation contain an equal number of gaseous particles. Indeed, both [tex][\mathrm{SO_2\, (g)}][/tex] and [tex][\mathrm{O_2\, (g)}][/tex] will increase if the pressure is increased through compression. However, because [tex]\rm SO_2\, (g)[/tex] and [tex]\rm O_2\, (g)[/tex] have the same coefficients in the equation, their concentrations are raised to the same power in the equilibrium quotient [tex]Q[/tex].
As a result, the increase in pressure will have no impact on the value of [tex]Q\![/tex]. If the system was already at equilibrium, it will continue to be at an equilibrium even after the change to its pressure. Therefore, no overall effect on the equilibrium position should be visible.
The molecular formula of benzene is C6H6. what is the empirical formula of benzene?
Which of the following methods can be used to competely separate a solution containing alcohol and water?
Answer:
separating funnel method
Which of the following characteristics is common to both acids and bases? They produce ions when dissolved in water They absorb oxygen ions when dissolved in water They increase hydrogen ions when dissolved in a solution They increase the hydroxide ions when dissolved in a solution
Answer:
They produce ions when dissolved in water.
Explanation:
Acids and bases have the characteristic in common to each other. Both of them have the property of reacting and dissolving in the water. Both acids and bases lead to the production of the ions when they are placed in a water solution. Acids produce Hydrogen ions when they are dissolved in water. Bases produce hydroxide ion when they are dissolved in water.
Answer:
A
Explanation:
Using VSEPR model, how is the molecular arrangement about the central atom (molecular geometry) for XeF4?
Answer:
Square planar.
Explanation:
Hello,
In this case, it can be demonstrated that the central atom Xenon in XeF₄ has a sp³d² hybridization which means that its geometry is likely to be octahedral. Nevertheless Applying by applying the valence shell electron pair repulsion (VSEPR) model to in order to minimize the repulsion among lone pairs, bond pairs and lone pair-bond pairs, we we realize repulsion is actually minimized when lone pairs are anti to one another and the fluorine atoms are in equatorial position, for that reason, the corrected and properly exhibited geometry or molecular arrangement of the compound turns out square planar. You can verify it on the attached picture.
Regards.
You wish to set up an electrochemical cell that has a copper anode and an
Eºcell value > 1.00 V. What should your cathode and cathode solution be?
True or false 12,785.000 has five significant digits.
Answer:
True
Explanation:
Significant digits include non-zero digits (unless the zero is between two non-zero numbers)
In 12,785.000, there are 5 non-zero digits:
1 2 7 8 5
ANSWER: the answer is true.
A constant current of 1.30 amps is passed through an electrolytic cell containing OsO2. How many hours will it take to produce 45.0 grams of osmium metal from this process
Answer:
9.8 h
Explanation:
From the question,
Os²⁻ - 2e⁻ = Os
From the equation above,
2 F of electron is needed to liberate 1 mole of osmium.
45 g of osmium contains 45/190 mole of osmium = 0.237 mole.
2 F ⇒ 1 mole.
2(0.237) F ⇒ 0.237 mole
0.474 F. will produce 45 g of osmium.
If 1 F = 96500 C ,
Then, 0.474 F = 45741 C,
But,
Q = it
t = Q/i....................... Equation 1
Given: Q = 45741 C, i = 1.30 A
Substitute into equation 1
t = 45741/1.3
t = 9.8 h.
Explain how passive and active transport are similar and how they are different.
Answer:
Sample Response: Both passive and active transport move substances into and out of the cell across the cell membrane. However, passive transport does not require the use of energy because molecules move from an area of high concentration to an area of low concentration. Active transport does require the use of energy because molecules move from an area of low concentration to an area of high concentration.
Explanation:
Active and passive transport are the two main biological processes which play an important role in providing the nutrients, oxygen, water and other essential molecules to the cells along with removing waste materials.
What are active and passive transport?The active transport involves the movement of molecules across a membrane against a concentration gradient which requires energy. The passive transport is the movement of molecules or ions across the cell membrane without using energy.
The differences between active and passive transport are: Active transport is a rapid process, passive transport is a slow process. Active transport transpires in one direction whereas passive one transpires bidirectionally. Active transport requires carrier proteins and energy whereas passive one does not require both.
The similarities among them are: both transport system require concentration gradient, both helps in homeostatic regulation and allow entry and exit of ions.
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Which of these is the basic unit of mass?
L
kg
cm
ml
If we add a catalyst to the following equation, CO + H2O + heat CO2 + H2, which way will the equilibrium shift?
Answer:
No effect.
Explanation:
Hello,
In this case, considering the widely studied Le Chatelier's principle, we can realize that the factors affecting equilibrium are concentration, temperature and pressure and volume if the reaction is in gaseous phase and with non-zero change in the number of moles. In such a way, by adding a catalyst to given reaction will have no effect on the equilibrium direction.
Best regards.
Lab safety is not only important in the classroom, but it is also important to follow
the rules at home, or on the bus. Accidents can happen anywhere and if proper safety
precautions aren't followed, someone can get hurt.
Last year in New York, students were burned when they were showing off their
science project at the bus stop.
In Rhode Island, a student kept chemicals in his locker for a later experiment, the
chemicals combined and exploded hurting students in the hallway.
In Brazil, students were practicing their experiment in a friend's garage, without
adult supervision, when there was an explosion. The explosion killed all 4 students.
Science can be a lot of fun but it is also dangerous if you aren't following safety
precautions.
Questions: Answer on the following slide.
1. What is needed from adults when conducting experiments at home?
2. What should always be followed when conducting experiments?
3. Why are chemicals so dangerous?
4. What is science?
YO
Answer:
Follow safety measures and safety rules to avoid any accident.
Explanation:
1. Follow all safety measures is needed from adults when they conducting any experiment at home in order to prevent any damage occurs due to that experiment.
2. Safety rules should always be followed when conducting an experiment at any place such as at home, class room and laboratory etc in order to avoid any accident.
3. Some chemicals are very dangerous because they are flammable and catch fire when allow it to the heat source. Some chemicals also cause suffocation by absorbing all the oxygen from the environment and as a result death occurs.
4. Science is a systematic study of physical objects through observation and experiments. Science is a knowledge gain from experiments.
What is the optimum pH to separate a mixture of lysine, arginine, and cysteine using electrophoresis
Answer:
9.5
Explanation:
Electrophoresis is a separation technique which involves the passage and the use of electric current in separating amino acid mixtures. The positively charged protein moves to the negative electrode while the negatively charged protein moves to the positive electrode which is in accordance to the law of attraction.
Proteins however perform optimally at the right temperature and pH. Studies shows that the optimum pH to separate a mixture of lysine, arginine, and cysteine using the electrophoresis method of separation is around 9.5
When titrating 50.0 mL of 0.10 M H2SO4 with 0.10 M NaOH, how many mL of NaOH will you have added to reach the 1st equivalence point?
Answer:
50.0mL 0.10M NaOH
Explanation:
The chemical equation of H₂SO₄ with NaOH to reach the first equivalence point is:
H₂SO₄ + NaOH → HSO₄⁻ + Na⁺ + H₂O
Where 1 mole of the H₂SO₄ reacts per mole of NaOH
The initial moles of H₂SO₄ are:
50.0mL = 0.0500L × (0.10 mol / L) = 0.0050 moles of H₂SO₄
As 1 mole of the acid reacts per mole of NaOH, to reach the first equivalence point we need to add 0.0050 moles of NaOH. As molarity of NaOH is 0.10M, the volume that we need to add to reach 1st equivalence point is:
0.0050 moles NaOH ₓ (1L / 0.10 moles NaOH) = 0.050L NaOH 0.10M =
50.0mL 0.10M NaOHThe solubility of gold (V) oxalate, Au2(C2O4)5 is 2.58 g/L. Calculate Ksp from this information.
Answer:
[tex]Ksp=3.39x10^{-14}[/tex]
Explanation:
Hello,
In this case, since the dissociation of gold (V) oxalate is:
[tex]Au_2(C_2O_4)_5(s)\rightleftharpoons 2Au^{5+}(aq)+5(C_2O_4)^{2-}(aq)[/tex]
In such a way, the equilibrium expression is:
[tex]Ksp=[Au^{5+}]^2[(C_2O_4)^{2-}]^5[/tex]
Thus, since the molar solubility of the gold (V) oxalate is computed by considering its molar mass (834 g/mol):
[tex][Au_2(C_2O_4)_5]=2.58\frac{g}{L} *\frac{1mol}{834g} =3.09M[/tex]
In such a way, since gold (V) is in a 2:1 molar ratio with the salt and the oxalate in a 5:1 in the chemical reaction, the corresponding concentrations at equilibrium are:
[tex][Au^{5+}]=3.09x10^{-3}\frac{mol}{L} *\frac{2molAu^{5+}}{1mol} =6.19x10^{-3}M[/tex]
[tex][(C_2O_4)^{2-}]=3.09x10^{-3}\frac{mol}{L} *\frac{5mol(C_2O_4)^{2-}}{1mol} =0.0155M[/tex]
Therefore, the solubility product turns out:
[tex]Ksp=(6.19x10^{-3})^2*(0.0155)^5\\\\Ksp=3.39x10^{-14}[/tex]
Regards.
your friend makes the statement that " I think water boils at a higher temperature than ethanol," to which step of scientific method does this statement belong? scientific law hypothesis experiment observation
hypothesis
need 20 characters hope this helps
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A is correct because the atomic number determines that there are two protons and electrons. The atomic mass minus the atomic number determines that there are two neutrons.
B is correct because the atomic number determines that there are two protons and neutrons. The atomic mass determines that there are four electrons in the electron shell.
D is correct because the atomic number determines that there are two protons and electrons. The atomic mass minus the atomic number determines the number of neutrons.
C is correct because the atomic number determines that there are two protons and electrons. The atomic mass determines that there are four neutrons in the nucleus.
Answer:
The correct answer is A.
Explanation:
Helium's Atomic Model has 2 Protons and 2 Neutrons, and on the outside it has 2 electrons circling around it.
Answer:
is A
Explanation:
A galvanic (voltaic) cell has the generic metals X and Y as electrodes. X is more reactive than Y, that is, X more readily reacts to form a cation than Y does. Classify the descriptions by whether they apply to the X or Y electrode.
a. Anode
b. Cathode
c. Loses mass
d. Electrons in the wire flow away from it
e. Anions from the salt bridge flow toward it
f. Cations from the salt bridge flow toward it
g. Gains mass
f. Electrons in the wire flow toward it
Answer:
X
Anode
Loses mass
Electrons in the wire flow away from it
Anions from the salt bridge flow toward it
Y
Cathode
Gains mass
Electrons in the wire flow toward it
Cations from the salt bridge flow toward it
Explanation:
A galvanic cell consists of an anode, a cathode and a salt bridge. The cathode is the negative electrode. The cathode increases in mass due to mass deposition. The cathode becomes increasingly negative as the cell reaction progresses, hence cations from the salt bridge flow towards it.
The anode is the positive electrode. It becomes more positive as the cell reaction progresses hence anions from the salt bridge flow towards it. The anode is the electrode where oxidation reaction occurs hence electrons are lost here and flow towards the cathode. The anode looses mass as the cell reaction progresses due to oxidation.
The following initial rate data are for the reaction of hypochlorite ion with iodide ion in 1M aqueous hydroxide solution: OCI+r → or +CI
Experiment [OCI] M I(-M) Rate (M/s)2
1 3.48 x 10-3 5.05 x 10-3 1.34 x 10-3
2 3.48 x 10-3 1.01 x 10-2 2.68 x 10-3
3 6.97 x 10-3 5.05 x 10-3 2.68 x 10-3
4 6.97 x 10-3 1.01 x 10-2 5.36 x 10-3
What is the rate law for this reaction?
a. Rate = [1-1
b. Rate = K[OCI-11-2
c. Rate = K[OCI,20-1
d. Rate = K[OCH
e. Rate = K[OC1-20-1
Answer:
Rate = k [OCl] [I]
Explanation:
OCI+r → or +CI
Experiment [OCI] M I(-M) Rate (M/s)2
1 3.48 x 10-3 5.05 x 10-3 1.34 x 10-3
2 3.48 x 10-3 1.01 x 10-2 2.68 x 10-3
3 6.97 x 10-3 5.05 x 10-3 2.68 x 10-3
4 6.97 x 10-3 1.01 x 10-2 5.36 x 10-3
The table above able shows how the rate of the reaction is affected by changes in concentrations of the reactants.
In experiments 1 and 3, the conc of iodine is constant, however the rate is doubled and so is the conc of OCl. This means that the reaction is in first order with OCl.
In experiments 3 and 4, the conc of OCl is constant, however the rate is doubled and so is the conc of lodine. This means that the reaction is in first order with I.
The rate law is given as;
Rate = k [OCl] [I]
Express 450 x 10-9 m (wavelength of blue light) in decimal notation (i.e., express
the number without using scientific notation).
Answer:
0.00000045 m is the wavelength of blue light in decimal
0.00000045 m is the wavelength of blue light in decimal without using scientific notation.
What is scientific notation?
Scientific notation is defined as a way of expressing numbers which are too large or too small so that they can be easily written in decimal form. It can be referred to the scientific form or the scientific index form or even the standard form.
Base ten notation is used by scientists, engineers as it helps in simplification of arithmetic operations. It contains the significant figures which include all non-zero numbers , the zeroes between significant digits and zeroes which are needed to be significant.
In scientific notation, the base should always be ten. The exponent should be a non-zero integer and it can be either positive or negative.
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An unknown compound’s semicarbazone melts at 162-165 degree Celsius. The compound does not give a silver mirror in the Tollens’ test. On reaction with KI/I2, NaOH/H2O no straw yellow precipitate forms. Identify the unknown. Explain your reasoning.
Answer:
Benzophenone
Explanation:
Given that:
an unknown compound’s semicarbazone melts at 162° -165°
The compound does not give a silver mirror in the Tollens’ test.
On reaction with KI/I2, NaOH/H2O no straw yellow precipitate forms.
The objective is to identify the unknown compound.
Since the unknown compound result to a semicarbazone, we can deduce that the unknown compound is a carbonyl compound. A carbonyl compound is either an aldehyde or ketone in nature. Also, the absence of silver mirror in the Tollens’ test carried out in the reaction confirms that the compound is a ketone because ketones will never give a silver mirror in Tollens’ test.
Similarly, on reaction with KI/I2, NaOH/H2O no straw yellow precipitate forms, that is an iodoform test. That implies that a keto-methyl group is absent in the unknown compound.
Finally, since the unknown compound melting point is between 162° -165° and Benzophenone semicarbazone melting point is 164°.
We can conclude that the unknown compound is Benzophenone semicarbazone
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Why does bromine (Br) have a smaller atomic radius than scandium (Sc)?
A. Scandium (Sc) has more energy shells than bromine (Br), making its atoms bigger.
B. Bromine (Br) has less neutrons than scandium (Sc), so it does not have as much mass.
C. Bromine (Br) has more electrons, which makes its energy sublevels more negative, which pulls them closer to the positively charged nucleus.
D. Electrons are added from right to left across the periodic table, so bromine (Br) does not have as many as scandium (Sc).
Answer:
Option (C) Bromine (Br) has more electrons, which makes its energy sublevels more negative, which pulls them closer to the positively charged nucleus.
Atomic radius is the size of the atom that measures from the center to the outermost electron. Bromine has a smaller atomic radius because of more number of electrons. Thus, option C is correct.
What is the periodic trend of radii?The elements are placed in the periods and groups in the periodic table based on the atomic number. Bromine belongs to group 17, period 4 in the periodic table, and scandium (Sc) to group 3, period 4.
In the periodic trend, the atomic radii of the element in the period decrease when moving from left-right. Here bromine and scandium both belong to the same period but differ in the group.
The number of electrons in bromine is more than the scandium element that in turn increases the force of attraction towards the nucleus making them have smaller radii.
Therefore, bromine has smaller radii.
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A 100.0 mL sample of 0.18 M HCl is titrated with 0.27 M KOH at 25°C. Determine the pH of the solution after the addition of 66.67 mL of the KOH titrant.
Answer:
pH = 7.0
Explanation:
The HCl reaction with KOH as follows:
HCl + KOH → H₂O + KCl
To find pH first we need to know how many moles of each reactant reacts as follows:
HCl = 0.1000L * (0.18 mol / L) = 0.018 moles HCl
KOH = 0.06667L * (0.27mol / L) = 0.018 moles KOH
That means all HCl reacts with all KOH and you will have in solution just water. The equilibrium of water is:
H₂O(l) ⇆ H⁺(aq) + OH⁻(aq)
K = 1x10⁻¹⁴ = [H⁺] [OH⁻]
As the amount of H⁺ = OH⁻:
1x10⁻¹⁴ = [H⁺]²
[H⁺] = 1x10⁻⁷M
as pH = -log [H⁺]
pH = 7.0Identify the product of radioactive decay and classify the given nuclear reactions accordingly.
a) 23488Ra â 23086Rn + _____
b) 23892U â 23893Np + _______
c) 24294Pu â 23892U + ______
d) 146C â 147N + ______
e) 2412Mg â 2412Mg + ________
Answer: a) [tex]_{88}^{234}\textrm{Ra}\rightarrow _{86}^{230}\textrm{Ra}+_{2}^{4}\textrm{He}[/tex]
b) [tex]_{92}^{238}\textrm{Ra}\rightarrow _{93}^{238}\textrm{Np}+_{-1}^{0}{\beta}[/tex]
c) [tex]_{92}^{238}\textrm{Ra}\rightarrow _{93}^{238}\textrm{Np}+_{-1}^{0}{\beta}[/tex]
d) [tex]_{6}^{14}\textrm{C}\rightarrow _{7}^{14}\textrm{N}+_{-1}^{0}{\beta}[/tex]
e) [tex]_{12}^{24}\textrm{Mg}\rightarrow _{12}^{24}\textrm{Mg}+_{0}^{0}{\gamma}[/tex]
Explanation:
A balanced nuclear equation is one in which the atomic number and mass number remains same on both sides of the equation i.e the number of protons and neutrons remain same.
General representation of an element is given as:
Z represents Atomic number
A represents Mass number
X represents the symbol of an element
a) [tex]_{88}^{234}\textrm{Ra}\rightarrow _{86}^{230}\textrm{Ra}+_{2}^{4}\textrm{He}[/tex]
b) [tex]_{92}^{238}\textrm{U}\rightarrow _{93}^{238}\textrm{Np}+_{-1}^{0}{\beta}[/tex]
c) [tex]_{94}^{242}\textrm{Pu}\rightarrow _{92}^{238}\textrm{Ra}+_{2}^{4}\textrm{He}[/tex]
d) [tex]_{6}^{14}\textrm{C}\rightarrow _{7}^{14}\textrm{N}+_{-1}^{0}{\beta}[/tex]
e) [tex]_{12}^{24}\textrm{Mg}\rightarrow _{12}^{24}\textrm{Mg}+_{0}^{0}{\gamma}[/tex]