Answers
Answer:
C. To remove any source of bias in an experience
Related Questions
Select all the correct images.
Select the atoms that belong to the same element.
16 protons 16 neutrons
16 electrons
11 protons 10 neutrons 11 electron
13 protons 14 neutrons 13 electrons
Answers
Answer:
11 protons 10 neutrons 11 electron
13 protons 14 neutrons 13 electrons
Explanation:
Isotopes are atoms of the same element having same atomic number but different mass numbers.
What would you use to measure
to measure an amount of solid sodium chloride(NaCI)
crystals to add to a 30 mL solution?
A. Triple Beam Balance that measures to the nearest 0.1 grams.
) B. 10 ml graduated cylinder.
Scale that can weigh up to 250 lbs.
D. Spectrophotometer that measures between 100 and 900 nanometers.
Answers
Identify the isoelectronic elements.
i. Cl-, F-, Br-, I-, At-
ii. Ne, Ar, Kr, Xe, He
iii. N3-, S2-, Br-, Cs+, Sr2+
iv. N3-, O2-, F-, Na+, Mg2+
v. Li+, Na+, K+, Rb+,Cs+
Answers
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.
i. Cl⁻, F⁻, Br⁻, I⁻, At⁻. NO. Cl⁻ has 18 electrons (17+1) and F⁻ has 10 electrons (9+1). ii. Ne, Ar, Kr, Xe, He. NO. Ne has 10 electrons and Ar has 18. iii. N³⁻, S²⁻, Br⁻, Cs⁺, Sr²⁺. NO. N³⁻ has 10 electrons (7+3) and S²⁻ has 18 (16+2).iv. N³⁻, O²⁻, F⁻, Na⁺, Mg²⁺. YES. They all have 10 electrons v. Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺. NO. Li⁺ has 2 electrons (3-1) and Na⁺ has 10 (11-1).Sodium is a highly reactive metal and
chlorine is a toxic gas, but when they
come together the resulting material,
sodium chloride, is essential for life.
Which of the following is true when
sodium and chlorine are brought into
contact with one another?
Answers
Answer:
NaCl
Explanation:
[tex]na + cl > nacl[/tex]
This is also a salt
describe how lyophobic sols are synthesize by dispersion method
Answers
Explanation:
For preparing lyophobic sol, the substance in bulk is broken down into particles of colloidal dimensions (Dispersion) or aggregating smaller particles into particles of colloidal dimensions (condensation).
How can you identify ethane from ethene
Answers
Why can characteristics properties be used to identify unknown substances
Answers
Characteristic properties are used because the sample size and the shape of the substance does not matter.
Which tasks can be used to start a descriptive investigation
Answers
Answer:
The tasks which form the preliminaries to a descriptive investigation are: Making careful objective observations. Asking the relevant scientific questions.
In an experiment, you added a base, NaOH, one mL at a time to 50 mL acetate buffer and recorded the pH. For the first 6 mL NaOH the pH increased from 4.5 to 4.9. At the 7th mL the pH was 6.6 and by the 8th mL the pH was 10.7. Knowing what you do about titrating acetate buffer with acid, is this experimental result what you expected or is it not expected
Answers
Answer:
yes the experimental result is the expected result .
Explanation:
When Titrating acetate buffer with acid the PH will decrease gradually from a more neutral PH to a more acidic level and this is because buffer solutions are prepared with weak acids and its conjugate base.
The results gotten from the continuous addition of base NaOH to the acetate buffer is the expected result because the base is been absorbed by the buffer solution and it is converted to a conjugate base of the buffer solution which will gradually increase the PH level of the solution as more conjugate base is formed due to the addition of more NaOH.
Unknown A melts at 113- 114oC. Known compounds 3-Nitroaniline and 4-Nitrophenol both melt at 112-114 oC. If A is mixed with 3-Nitroaniline and the melting point becomes broad and depressed, what must A be __________A) 3-Nitroaniline B) 4-Nitrophenol C) Both
Answers
Answer:
C) Both
Explanation:
Whenever we mix any pure form of a compound with some other form of a compound which is not in the other standard pure state, this results in the melting point of mixture to get dispersed and it becomes broad form.
Thus, when a known compound of 3-Nitroaniline mixes with both 3-Nitroaniline and 4-Nitrophenol, the melting point of the compound becomes depressed and board.
Thus the correct option is (C).
Can the properties of different substances in a mixture be used to separate them?
Answers
Answer: here you go
Explanation:
Physical properties of the substances in a mixture are different, so this allows the substances to be separated. Think about the example of a mixture of salt water.
Answer:
Mixtures can be classified on the basis of particle size into three different types: solutions, suspensions, and colloids. The components of a mixture retain their own physical properties. These properties can be used to separate the components by filtering, boiling, or other physical processes.
Explanation:
What would happen to the Earth's hydrosphere if there were no atmosphere?
Answers
Project: Global Temperature Change
Research and write an essay about the rise of global temperatures over the past century.
PLEASE HELP THIS IS 10% OF MY GRADE
Answers
Answer:
Im sorry i cant write a whole essay right now but these sourcea could help.
https://climate.nasa.gov/effects/
https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature
Answer:
have you done it yet?
Explanation:
..
HELLP I NEEED HELP NOWW NO GUESSING FRFR
What will happen when a piece of magnesium metal is dropped into a beaker
containing a 1 M solution of copper(II) chloride?
Mg2+ + 2e → Mg(s) ° =- 2.37 V
Cu2+ + 2e → Cu(s) £° = + 0.34 V
Answers
What kind of magma produce the most violent eruptions
Answers
Answer:
Explosive eruptions from Composite or strato volcano
Explanation:
since they have multiple holes of exit, they can get pretty explosive.
Answer this please t
Lol
Answers
Answer: trial b
Explanation:
what would be the mass of 44.8 L of CO2 gas at STP?
show work if possible
Answers
Answer:
[tex]m=88.02g[/tex]
Explanation:
Hello there!
In this case, for this ideal gas law problem, it turns out necessary for us to remember that one mole of any gas is contained in 22.4 L at STP and therefore, we can use the following ratio to calculate the moles in 44.8 L of CO2:
[tex]\frac{1mol}{22.4L} =\frac{x}{44.8L}\\\\x= \frac{1mol*44.8L}{22.4L}=2mol[/tex]
Finally, since the molar mass of CO2 is 44.01 g/mol, we calculate the mass as follows:
[tex]m=2mol*\frac{44.01g}{1mol}\\\\m=88.02g[/tex]
Regards!
Soda contains phosphoric acid (H3PO4). To determine the concentration of phosphoric acid in 50.0 mL of soda, the available phosphate ions are precipitated with excess silver nitrate as silver phosphate (418.58 g/mol). The dry Ag3PO4 is found to have a mass of 0.0576 g. What is the concentration of phosphoric acid in the soda?
Answers
Answer:
0.0270w/v% H3PO4 in the soda
Explanation:
All phosphates reacts producing Ag3PO4. To solve this question we must convert the mass of Ag3PO4 to moles. These moles = moles of H3PO4. We can find, thus, the mass of H3PO4 and the w/v% as follows:
Moles Ag3PO4 -Molar mass: 418.58g/mol-
0.0576g * (1mol / 418.58g) = 1.376x10⁻⁴ moles Ag3PO4 = moles H3PO4
Mass H3PO4 -Molar mass: 97.994g/mol-
1.376x10⁻⁴ moles Ag3PO4 = moles H3PO4 * (97.994g/mol) = 0.0135g H3PO4
w/v%:
0.0135g H3PO4 / 50.0mL * 100 =
0.0270w/v% H3PO4 in the sodaThere are four different starting molecules that one might use to synthesize the illustrated alkyl halide as the major product using an electrophilic addition reaction. Please draw all four of them.
Answers
Answer:
Explanation:
An electrophilic addition reaction occurs when an electrophile attacks a substrate, with the end result being the inclusion of one or many comparatively straightforward molecules along with multiple bonds.
In the given question, the hydrogen bromide provides the electrophile while the bromide is the nucleophile. The mechanism proceeds with the attack of the electrophile on the carbon, followed by deprotonation. This process is continued with a formation of carbocation and the bromide(nucleophile) finally bonds to the carbocation to form a stable product.
The first diagram showcases the possible various starting molecules for the synthesis while the second diagram illustrates their mechanism.
Predict the products from theses reaction, and balance the equations. Include phase symbols.
Reaction : K(s)+Cl2(g)⟶
Reaction :Cu(s)+O2(g)⟶
Answers
Answer:
2 K(s) + Cl₂(g) ⟶ 2 KCl(s)
2 Cu(s) + O₂(g) ⟶ 2 CuO(s)
Explanation:
Both reactions are synthesis reactions (two substances combine to form another).
Reaction: K(s) + Cl₂(g) ⟶
The product is the binary salt KCl. The balanced chemical equation is:
2 K(s) + Cl₂(g) ⟶ 2 KCl(s)
Reaction: Cu(s) + O₂(g) ⟶
The most likely product is the metal oxide CuO. The balanced chemical equation is:
2 Cu(s) + O₂(g) ⟶ 2 CuO(s)
Suppose you are trying to separate three Proteins using Gel-Filtration chromatography. The sizes of each are given below:
Protein A: 1200 kDa
Protein B: 2000 kDa
Protein C: 800 kDa
Which protein will be the first to emerge from the column?
Answers
Answer: The correct answer is Protein B.
Explanation:
Gel-filtration chromatography is a separation technique that is based on the size of the molecules in a compound. It is also known as size-exclusion chromatography in which the eluent (carrier) used is an aqueous solution.
The matrix that is used is a porous material. When the sample is inserted in the column, the smaller particles interact strongly with the matrix than the large ones. Thus, as the eluent is passed through the matrix, larger molecules come out first, and the smallest molecule comes out last.
Given sizes of the proteins:
Protein A: 1200 kDa
Protein B: 2000 kDa
Protein C: 800 kDa
As protein B has the largest size of all the given proteins, it will emerge out first from the column.
Hence, the correct answer is Protein B.
A certain first-order reaction is 27.5 percent complete in 8.90 min at 25°C. What is its rate constant?
Answers
Answer:
[tex]k= 0.145min^{-1}[/tex]
Explanation:
Hello there!
In this case, according to the given information, it turns out necessary for us remember that the first-order kinetics is given by:
[tex]ln(A/A_0)=-kt[/tex]
Whereas the 27.5% complete means A/Ao=0.275, and thus, we solve for the rate constant as follows:
[tex]k=\frac{ln(A/A_0)}{-t}[/tex]
Then, we plug in the variables to obtain:
[tex]k=\frac{ln(0.275)}{-8.90min}\\\\k= 0.145min^{-1}[/tex]
Regards!
how many moles of neon gas have a volume of 0.84 L and a pressure of 4.6 atm at 222k
Answers
Answer:
n = 0.21 moles
Explanation:
Given that,
Volume, V = 0.84 L
Pressure, P = 4.6 atm
T = 222 K
We need to find the number of moles of Neon gas. We know that,
PV = nRT
Where
n is the number of moles
R i the gas constant, R = 0.08206 L-atm/mol-K
Put all the values,
[tex]n=\dfrac{PV}{RT}\\\\n=\dfrac{4.6\times 0.84}{0.08206 \times 222}\\\\n=0.21\ \text{moles}[/tex]
So, there are 0.21 moles of Neon gas.
The strongest base that can exist in a solution in appreciable concentration is the conjugate base of the solvent.
a. True
b. False
Answers
Answer:
a. True
Explanation:
From the basic concepts of acids and bases, we know that when a base accepts a hydrogen ion (H⁺), it forms a conjugate acid which can accept again the H⁺ ion:
B⁻ + H₂O ⇆ BH + OH⁻
The stronger the base, the weaker the conjugate base. Thus, as more strength has a base, lesser strength will have the conjugate base (it will not be able to accept again the H⁺ ion). For example, when water (H₂O) loses its H⁺ , it forms the conjugate base OH⁻. So, OH⁻ is the stronger base that can exist in an aqueous solution.
H₂O ⇆ H⁺ + OH⁻
In fact, strong bases are hydroxides, such as NaOH or KOH.
Water is considered to be a diatomic molecule because it composed of two different atoms. True or false?
Answers
Answer:
false
Explanation:
False, water is a polyatomic molecule made up of two atoms of oxygen and 1 atom of hydrogen.
Explanation:
The monoatomic molecule is composed of a single atom of an element.For example: Helium(He) , argon(Ar) etc.The diatomic molecule is composed of two atoms of the same or different elements.For example: hydrochloric acid (HCl), sodium chloride (NaCl) etc.The polyatomic molecule is composed of three or more than three atoms of the same or different elements.For example: water ([tex]H_2O[/tex]), sodium hydroxide(NaOH) etc.So, from this, we can conclude that water is a polyatomic molecule made up of two atoms of oxygen and 1 atom of hydrogen.
Learn more about types of molecules here:
brainly.com/question/3213630?referrer=searchResults
brainly.com/question/4979095?referrer=searchResults
During a chemical reaction, an iron atom became the ion Fe2+. What happened to the iron atom?
Answers
Explanation:
Iron atom is been oxidised as it losses 2 electron to form 2 + ion.
does light appears to travel in straight lines. travelling from light sources until it hits the surface of an object?? (Truer or False) if your answer is true then what is the reason why does light appears to travel in straight lines??.
Answers
Answer:
true once light has been produce it will keep travelling jn straight parts until it hits something else
Which of the following can be mixed in solution with NH3 to make a buffer?
Answers
Answer:
c. NaOH
Explanation:
just took the quiz
Identify which of the compounds below are amphoteric.
a. hydrogen sulfide ion
b. sulfuric acid
c. dihydrogen phosphate
d. water
e. carbonate ion
Answers
Hydrogen sulfide ions, dihydrogen phosphate, and water are amphoteric. Therefore, option (a), (c), and (d) are correct.
What is amphoteric?Amphoteric can be stated as any compound that can be mixed with other compounds both as a base and an acid. Water is amphoteric as it can be transformed into a compound that can be mixed as an alkali or an acid.
Amphoterism is explaining the reactivity of a compound that indicates alkaline nature when mixed with an acid and describes acidic characteristics in an alkaline environment.
When acid reacts with water, it forms H₃O⁺ ion adding an H⁺ ion from the acid. When water is combined with a base, it donates a hydrogen H⁺ ion to the base and releases a hydroxide ion.
Besides water, there are many oxides and hydroxides are utilized in amphoterism. The substances that have both characteristics acids are proton donors and bases are proton acceptors are identified as amphoteric substances.
Therefore, HS⁻, H₂O, and H₂PO₄⁻ are amphoteric in nature.
Learn more about amphoteric, here:
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A student dissolves 7.9 g of stilbene (C14H12) in 475. mL of a solvent with a density of 1.03 g/mL. The student notices that the volume of the solvent does not change when the stilbene dissolves in it. Calculate the molarity and morality of the students solution. Round both of your answers to 2 significant digits.
Answers
Answer:
Molarity: 0.092M
Molality: 0.090m
Explanation:
Molarity, M, is defined as the moles of solute (In this case, C14H12 -Molar mass: 180.25g/mol-) in 1L of solution.
The molality, m, are moles of solute per kg of solvent.
Molarity:
Moles solute:
7.9g * (1mol/180.25g) = 0.04383 moles
Liters solution:
475mL = 0.475L
Molarity: 0.04383 moles / 0.475L = 0.092M
Molality:
kg solvent:
475mL * (1.03g/mL) = 489.25g = 0.48925kg
Molality:
0.04383 moles / 0.48925kg = 0.090m
