PLEASE HELP MEEEEE (using 98 points to post)
Given that the molal freezing point depression constant (kf) for methyl alcohol (CH3OH) is -0.83 oC/molal, how much will the freezing point of methyl alcohol be lowered if 46.0 g of glycerine (C3H8O3) is added to 1.00 kg of methyl alcohol? (must show work, correct unit and correct answer)
2.86 °C = (1) (1.86 °C kg mol-1) (x / 0.750 kg)
2.86 °C = (2.48 °C mol-1) (x)
x = 1.1532 mol
33.7 g / 1.1532 mol = 29.2 g/mol
Relating ideas explain why ionic crystals melt at much higher temperatures than typical covalent molecular crystals.
The heating curve below shows the temperature change that occurs as a solid is heated. What is occurring at segment CD of the graph? (3 points)
A line graph showing the heating curve of a substance being heated from the solid phase all the way to the gas phase. From left to right across the x-axis, the different regions of the heating curve are labeled with variables A through F. First, there is an incline with a positive slope labeled AB, followed by a horizontal region labeled BC. Then there is another incline with a positive slope labeled CD, followed by another horizontal region labeled DE. The end of the heating curve shows another incline with a positive slope labeled EF.
boiling a liquid
melting a solid
heating a liquid
heating a solid
50 POINTS!! 10. A weak acid with an initial pH of 3.2 was titrated with a strong base. 15 mL of 0.1 M NaOH was added to the acid to reach the equivalence point at a pH of 8.6. What would you expect the approximate pH of the analyte to be after the first 5 mL of 0.1 M NaOH was added?
8.6
3.4
5.1
7.2
Answer : Option C) 5.1
If we consider any weak acid and strong base titration. We usually observe that the pH initially rises quite fast then remains constant during the buffer region before rising rapidly to the end point.
So, if 5 mL of NaOH is considered to be the one third of the way to the endpoint, then after the initial rise which will be more than 3.4 and reaching to the buffer region before rising to the endpoint.
Now, if endpoint has pH of 8.6 a buffer region around 5 is a good but the acid could be acetic acid which has similar pH endpoints with the pKa of 4.74 - so buffer region around 5 will be the good condition.
And hence pH of 5.1 is the most probably the right answer.
5.1 would be the clostest answer
what temperature does blood boil at (in Celsius Kelvin and Fahrenheit)
Blood boils at a temperature close to water's boiling point: 100°C, 373 K, or 212°F. This boiling point slightly varies due to dissolved substances. Understanding these values illustrates the relationship among different temperature scales.
When considering the temperature at which blood boils, it primarily depends on its composition, but generally, it is close to the boiling point of water. The boiling point of water is an important reference and is commonly known for each temperature scale:
Celsius (°C): Water boils at 100°C.Kelvin (K): Water boils at 373 K.Fahrenheit (°F): Water boils at 212°F.Human blood is mostly water, and hence its boiling point is similarly close; however, due to the presence of dissolved proteins, salts, and other substances, the exact boiling point may slightly vary. At normal atmospheric pressure, it is approximately 100°C (373 K or 212°F). This concept is an important illustration of the relationship among the temperature scales.
According to the following electron structure, how many valence electrons do these fluorine atoms have? F= 1s12s22p5
Fluorine atoms have seven valence electrons according to their electron configuration, which is reflected in their belonging to Group 7A of the periodic table and is also depicted in their Lewis dot structure.
According to the given electron structure of fluorine (F=1s22s22p5), fluorine atoms have seven valence electrons. The electron configuration indicates that there are two electrons in the first energy level (1s2) and seven electrons in the second energy level (2s22p5). Since the second energy level is the outermost shell, these seven electrons are considered the valence electrons.
Fluorine belongs to Group 7A in the periodic table, which means it is expected to have seven valence electrons. This is confirmed by the electron configuration. These valence electrons are represented in a Lewis dot structure by placing seven dots around the symbol for fluorine (F).
Which determines whether the fire will have open flames?
Question 4 options:
flash point
fuel-air mix
exothermic energy
type of fuel
Which statement describes the difference between chemical reactions and nuclear decay
Chemical reactions can result in new compounds, while nuclear reactions can result in new elements.
The "gas" that was used in ww i contained phosgene. into what corrosive chemical was this gas changed when it met with the moisture in the lungs
Which element is likely to be chemically unreactive? krypton (8 valence electrons) rubidium (1 valence electron) silicon (4 valence electrons) magnesium (2 valence electrons) bromine (7 valence electrons)?
If generating a key for this data, what is the correct sequence from bottom to top?
Generating a key from bottom to top signifies rearranging data in a particular order, often used in sorting or indexing processes. The actual sequence depends on the set rules, such as alphabetically or numerically.
Explanation:The correct sequence from bottom to top when generating a key for data, generally implies rearranging the data in a specific order. Let's consider a scenario in which we have data items named A, B, C, and D from bottom to top. In this case, the correct sequence from bottom to top might be D, C, B, A, assuming we're ordering in reverse-alphabetical order. However, the exact sequence can depend on the specific criteria or rules you're using to generate the key.
These keys are often used in computer operations such as sorting and indexing to manage and locate data efficiently. It's always important to understand the specific context in which the key is being applied for an accurate sequence.
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When copper reacts with silver nitrate according to the equation, the number of grams of copper required to produce 432 grams of silver is -?
Final answer:
To produce 432 grams of silver from the reaction of copper with silver nitrate, 127.23 grams of copper are required according to stoichiometry and the mole ratio from the balanced equation.
Explanation:
To determine the number of grams of copper required to produce 432 grams of silver in the reaction with silver nitrate, we must first understand the balanced chemical equation:
Cu(s) + 2 AgNO3(aq) → Cu(NO3)2(aq) + 2 Ag(s)
From this balanced equation, we can see that one mole of copper reacts with two moles of silver nitrate to produce one mole of copper(II) nitrate and two moles of silver. To solve the problem, we need three molar masses: that of copper (63.55 g/mol), silver nitrate (169.88 g/mol), and silver (107.87 g/mol). Using stoichiometry, we can set up the calculation as follows:
432 g Ag x (1 mol Ag / 107.87 g Ag) x (1 mol Cu / 2 mol Ag) x (63.55 g Cu / 1 mol Cu) = grams of Cu required
By calculating, we get:
432 g Ag / 107.87 g/mol Ag = 4.004 mol Ag
4.004 mol Ag x 1 mol Cu / 2 mol Ag = 2.002 mol Cu
2.002 mol Cu x 63.55 g/mol Cu = 127.23 g Cu
Therefore, 127.23 grams of copper are required to produce 432 grams of silver when copper reacts with silver nitrate according to the balanced equation.
Nuclear power plants produce a waste product of cesium-137, which has a half-life of 30 years. how long would it take for the cesium to decay to 1/8 of its original amount?
Answer:
90 years
Explanation:
it takes three halves of one to get to 1/8.
So 30 times 3 = 90
Which of the following statements is not true of the process of nuclear fission? (3 points) It is the process used in most nuclear power plants. It only occurs in very small atoms with low mass. It involves the splitting of an atom's nucleus. It can occur in a chain reaction.
An analogy to define the term half-life?
The molarity of a solution of 5.0 g of kcl in 100. ml of solution is ________.
Answer: The molarity of solution is 0.67 M
Explanation:
To calculate the molarity of solution, we use the equation:
[tex]\text{Molarity of the solution}=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (in mL)}}[/tex]
We are given:
Mass of solute (KCl) = 5.0 g
Molar mass of potassium chloride = 74.55 g/mol
Volume of solution = 100 mL
Putting values in above equation, we get:
[tex]\text{Molarity of solution}=\frac{5g\times 1000}{74.55g/mol\times 100mL}\\\\\text{Molarity of solution}=0.67M[/tex]
Hence, the molarity of solution is 0.67 M
Which two gases are most abundantly emitted in volcanic outgassing?
a. nitrogen and oxygen
b. hydrogen and helium
c. carbon dioxide and methane
d. water vapor and sulfur dioxide?
Answer: d. water vapor and sulfur dioxide?
As per result of studies done on volcanic eruptions, Water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2) are the most common volcanic gases abundantly emitted in volcanic outgassing. Other gases like carbon monoxide, methane and hydrogen are released in lesser amounts.
Answer:
water vapor and sulfur dioxide.
Which of the following objects does not decompose?
A) Tinfoil
B) Plastic Water Bottle
C) Lumber
D) Milk Carton
Final answer:
A) Tinfoil, which is made of aluminum, does not decompose as it is not an organic material. Plastic water bottles and milk cartons can take significant time to decompose due to their plastic components, while lumber, being organic, does decompose naturally.
Explanation:
The object that does not decompose among the ones listed is A) Tinfoil. Decomposition is a process that typically involves the breakdown of organic material by microorganisms. Tinfoil, which is made of aluminum, is not an organic material and thus does not decompose in the same way organic substances, like lumber, do. A plastic water bottle can take a very long time to decompose, often hundreds of years, but it can eventually break down, although not as readily as organic materials. A milk carton typically contains both paper, which is organic and degradable, and a plastic lining, which can take a considerable amount of time to decompose. As such, milk cartons often have components that can degrade and others that are very resistant to degradation. On the other hand, lumber, which is wood, will decompose over time as it is an organic material.
Write equations for the ionization of hno3 in water and the reaction of co32- with water. for each equation, identify the hydrogen-ion donor and hydrogen-ion acceptor. then label the conjugate acid-base pairs in each equation.
where are the most reactive nonmetals located on the periodic table?
a. the second column from the right side of the table
b. the uppermost complete row of the table
c. the column at the far left side of the table
d. the rows at the bottom of the table connecting two sections
The most reactive nonmetals are found in the column second from the right side of the periodic table, also known as Group 17 or the halogens. They are highly reactive because they need to gain just one electron to complete their outer electron shell. Fluorine is the most reactive nonmetal.
Explanation:The most reactive nonmetals are located in the upper right section of the periodic table, in the column that is second from the right side. This column is known as Group 17, or the halogens. Halogens are highly reactive due to their propensity to gain an electron to fill their outer electron shells, and they exhibit rich variety of chemical behaviors.
Elements belonging to the same column or group, such as the halogens, share many chemical characteristics because they have the same number of valence electrons.
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Why can you predict the base sequence of one strand in a molecule of DNA if you know the sequence of the other strand?
A-The order of bases in the two strands are identical.
B-There are only two base sequences, and a DNA molecule has each.
C-In DNA, each base pairs up with only one other base.
D-Every molecule of DNA has the same base sequence.
The sequence of bases on one strand of DNA can be predicted from the other due to specific base pairing rules, with adenine pairing with thymine, and cytosine with guanine, a principle foundational to DNA replication and repair mechanisms. Option c
The ability to predict the base sequence of one DNA strand when the sequence of the complementary strand is known is due to base pairing rules, which are critical for DNA replication and maintenance. In this specific pairing, adenine (A) always binds to thymine (T), and cytosine (C) always binds to guanine (G).
The bases on one strand form hydrogen bonds with the bases on the opposite strand, leading to a complementary base sequence: whenever there is an 'A' on one strand, there is a 'T' opposite it, and for every 'C' there is a 'G'. This strict pairing, which was elucidated in the Watson-Crick model of DNA, essentially allows one to recreate one strand's sequence from the other.
An example of complementary base pairing would be a DNA strand with the sequence 5'-AATTGGCC-3' having a complementary strand with the sequence 3'-TTAACCGG-5'..
Due to the nature of these interactions, the process of DNA replication involves separating the two strands and using each as a template to create a new complementary strand. This results in two DNA molecules where one strand is original and the other newly synthesized. The redundancy in information encoded by the complementary strands is a crucial aspect of genetic fidelity and repair mechanisms in the cell, ensuring the DNA's integrity over generations.
How is heat transferred through thermal conduction?
Answer:
Heat is transferred through contact between molecules.
Explanation:
a-p-e-x
In order for plants to go through photosynthesis, they must use
A. X rays.
B. visible light.
C. infrared rays.
D. ultraviolet light.
Which of the following is most likely to increase the rate of a reaction?
a. reducing the activation energy
b. decreasing the temperature
c. decreasing the concentration of the reactant in the reaction vessel
d. increasing the volume of the reaction vessel
Question 13 unsaved the nonmetals in groups 5a, 6a, and 7a: question 13 options: lose electrons when they form ions. form ions with charges of 3-, 2-, and 1-, respectively. form positively charged ions. form ions with a numerical charge equal to their group number.
How does the law of conservation of mass apply to this reaction: C2H4 + O2 → H2O + CO2?
Which one of these elements is an alkaline earth metal
A) most reactions involve bond breaking and bond making. this equation shows what happens when methane (ch4) burns in oxygen (o2). mark the bonds broken in blue and the bonds formed in red.\
When CH₄ burns with the presence of O₂, CO₂ and H₂O are formed as the products. The balanced equation is;
CH₄ + 2O₂ → CO₂ + 2H₂O
When the reaction happens, 4 C-H bonds of CH₄ and O=O bond of O₂ are broken down to form 2 C=O bonds in CO₂ and 2 O-H bonds in H₂O.
The broken and formed bonds are marked in the image.
Consider the rate law below.
What effect does doubling the concentration of each reactant have on the rate? The rate increases to two times the original rate. The rate increases to four times the original rate. The rate increases to six times the original rate. The rate increases to eight times the original rate.
When an arrhenius base is dissolved in h2o, the only negative ion present in the solution is?
What volume of hydrogen will be produced at STP by the reaction of 78.33g of aluminum with excess water
To find the volume of hydrogen gas produced at STP from the reaction of 78.33g of aluminum with excess water, calculate the moles of aluminum, convert that to moles of hydrogen gas using stoichiometry, and then use the molar volume at STP to find 97.44 liters of hydrogen gas.
Explanation:To determine the volume of hydrogen produced at STP (Standard Temperature and Pressure) by the reaction of aluminum with excess water, we first need to write the balanced chemical equation for the reaction.
For aluminum reacting with water yielding aluminum hydroxide and hydrogen gas, the balanced equation is:
2 Al(s) + 6 H₂O(l) → 2 Al(OH)3(aq) + 3 H₂(g)From this equation, we can see that 2 moles of aluminum produce 3 moles of hydrogen gas. To find the moles of aluminum in 78.33g, we use the molar mass of aluminum (approximately 26.98 g/mol).
Calculate the number of moles of aluminum:Thus, the reaction of 78.33g of aluminum with excess water will produce 97.44 liters of hydrogen gas at STP.