Answer:
4.83 km
Explanation:
Let's consider the following subtraction.
4.910 km - 0.08 km
For an addition or a subtraction, the rule for significant figures is as follows: limit the reported answer to the rightmost column that all numbers have significant figures in common, in this case, 2 figures after the decimal point.
4.910 km - 0.08 km = 4.83 km
Which of the following reactions does the coenzyme biotin catalyze?
a. carbon adjacent to an ester or keto group.
b. decarboxylation of an a-carboxy acid.
c. decarboxylation of an a-keto acid.
d. carboxylation of an a-carboxy acid.
e. decarboxylation of a carbon adjacent to an ester or keto group.
Answer:
c. decarboxylation of an a-keto acid.
Explanation:
Decarboxylation refers to the removal of the carboxyl group from a carboxylic acid and thus releasing carbon dioxide. Decarboxylases are enzymes that speed up the removal of the carboxyl group from acids. These reactants could be amino acids, alpha-keto acids, and beta-keto acids. Biotin is known to catalyze the decarboxylation of malonyl CoA to acetyl CoA during fatty acid synthesis.
Malonyl CoA is converted to acetyl CoA after decarboxylation assisted by biotin also known as Vitamin H. Alpha keto acids are involved in fatty acids synthesis and Malonyl CoA is an alpha-keto acid because the keto group is located in the first carbon near the carboxylic acid group. Keto acids have both a carboxyl group and a ketone group.
Question 4 of 10
Which phrase best describes how scientists use the data they collect?
A. To convince students to repeat their experiments
B. To prove that a scientific hypothesis is correct
C. To persuade other people to believe the same things
D. To decide if there is support for an experiment's conclusions
Answer:
D.
Explanation:
Apex
Scientists use the data which they collect to decide if there is support for an experiment's conclusions and to test if it is in support or against the hypothesis proposed.
What is hypothesis?Hypothesis can be defined as an assumption which is made for the sake of argument . It is an interpretation of a practical condition for which action needs to be taken.It is defined as a tentative assumption which is made to test logical consequences.It is an antecedent clause of a statement which is conditional.
It is constructed before research. There are six types of hypothesis 1)simple hypothesis 2) complex hypothesis 3) directional hypothesis 4)non-directional hypothesis 5) null hypothesis 6)casual hypothesis
The hypothesis should be clear and precise, it must be specific and way of explanation of hypothesis should be simple.
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What feature is common to all microscopes, and how is this feature related in the word "microscope"?
Answer:
All microscopes allow visualization of samples that are too small to be viewed by the naked eye. Microscopes let scientists make observations of microscopic objects.
Explanation:
During the titration of a diluted vinegar sample with a sodium hydroxide solution, the volume of sodium hydroxide used was less than expected. Which of the following could account for the lower than expected volume?
A. The sodium hydroxide solution had been allowed to stand exposed to the air for a long time prior to the titration.
B. The volumetric flask used to prepare the diluted vinegar solution was rinsed with water prior to use.
C. The burette used to deliver the sodium hydroxide solution was rinsed with water prior to use.
D. The pipette used to deliver the vinegar solution was rinsed with water prior to use.
Answer:
B and D could be true
Explanation:
A volume of sodium hydroxide less than expected could occurs for two reasons:
The real concentration of sodium hydroxide was higher than expected or the amount of vinegar added was less than expected:
A. The sodium hydroxide solution had been allowed to stand exposed to the air for a long time prior to the titration. FALSE. A long expose to the air decreases concentration of the NaOH.
B. The volumetric flask used to prepare the diluted vinegar solution was rinsed with water prior to use. TRUE. You add a less amount of vinegar doing you require less amount of NaOH than expected.
C. The burette used to deliver the sodium hydroxide solution was rinsed with water prior to use. FALSE. Thus, you add a less amount of NaOH than expected. To explain the matter, you add more NaOH than expected.
D. The pipette used to deliver the vinegar solution was rinsed with water prior to use. TRUE. Again, you are adding a less amount of Vinegar than expected doing the necessary NaOH during titration less than expected
To convert m-ethylaniline to m-ethylfluorobenzene, it should be treated with nitrous acid followed by _____________.
Answer:
[tex]NaBF_4[/tex]
Explanation:
In this reaction, we must exchange the amino group ([tex]NH_2[/tex]) for a fluorine atom ([tex]F[/tex]). Also, the first step in this reaction is the addition of nitrous acid.
We must remember that the amino group in the presence of nitrous acid produces a diazonium salt. The [tex]N_2[/tex] group is a very good leaving group and many benzene derivatives can be produced from this intermediate (see figure 1).
If what we want is to bond a fluorine atom we must use [tex]NaBF_4[/tex] to be able to produce m-ethylfluorobenzene (see figure 2).
I hope it helps!
How would you describe the molecule in the image?
A.) Both Polar and Hydrophilic
B.) Polar
C.) Nonpolar
D.) Hydrophobic
E.) Hydrophilic
F.) Both Nonpolar and Hydrophobic
The main type of attractive forces between molecules of carbon tetrabromide (cbr4) are:_______
Answer:
Vanderwaals forces
Explanation:
CBr4 is a nonpolar molecule, nonpolar molecules usually possess vanderwaals forces between their molecules as their main attractive force.
CBr4 is nonpolar because the tetrahedral arrangement of the C-Br bonds cancel out the individual dipole moments of each C-Br bond thereby making the compound nonpolar, hence the answer above.
How many significant figures are in 0.003450?
Answer:
4
Explanation:
Four significant figures
A sample was collected from a computer keyboard and a toilet seat using two separate cotton swabs. Then, each swab was wiped on a petri dish and left to grow for 5 days.
*Which location had the most bacteria present? The computer keyboard or the toilet seat?
*What steps can you take to prevent the spread of bacteria in the office setting?
Answer:
toilet seat and washing of hands ✋ very well
A rectangular box has a length of 12 cm, a width of 20 cm, and
a height of 5 cm. What is the volume of the box in ml?
Answer:
1200
Explanation:
bc 12x20x5
Answer:
The volume of the rectaganle is 1200cm.
Explanation:
U take Length×width×height
so l×w×h = 12cm × 20 cm × 5cm
Which list includes all the steps of a descriptive investigation? A. is asking questions, making observations, collecting data, comparing, and forming a conclusion B. Asking questions, making observations, experimenting, analyzing data, and forming a conclusion C. Asking questions, making observations, experimenting, and overcoming limitations D. Asking questions, making observations, collecting data, and forming a conclusion
Answer: D
Explanation:
Answer: B
Explanation: Those are the steps and I took the quiz and got it right
A crystalline form of solid fat is ?
_ _ _ _ _ _ _ _ _ _
( 10 letter word )
A crystalline form of solid fat is Glycerides
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Determine the pH of a solution of 0.00278 M of HClO4. Report the answer to two digits past the decimal.
Answer:
The pH of a solution of 0.00278 M of HClO₄ is 2.56
Explanation:
pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance and is calculated as:
pH= - log [H⁺]= - log [H₃O⁺]
On the other hand , a Strong Acid is that acid that in an aqueous solution dissociates completely. In other words, a strong acid completely dissociates into hydrogen ions and anions in solution.
HClO₄ is a strong acid, so in aqueous solution it will be totally dissociated. Then, the concentration of protons is equal to the initial concentration of acid and the pH will be calculated:
pH= - log 0.00278
pH= 2.56
The pH of a solution of 0.00278 M of HClO₄ is 2.56
which statement describes a risk of technological design of headphones?
Answer: maybe a choking hazard for the ones with wires
Explanation:
What do you think pseudo- means?
Pseudo in chemistry means a reaction which is not first-order reaction naturally but made first order by increasing or decreasing the concentration of one or other reactant is known as Pseudo first order reaction.Pseudo means "fake".
An unknown weak acid with a concentration of 0.086 M has a pH of 1.80. What is the Ka of the weak acid?
Answer:
2.90 × 10⁻³
Explanation:
Step 1: Given data
pH: 1.80
Concentration of the weak acid (Ca): 0.086 M
Step 2: Calculate the concentration of H⁺
We will use the following expression.
pH = -log [H⁺]
[H⁺] = antilog -pH = antilog -1.80
[H⁺] = 0.0158 M
Step 3: Calculate the acid dissociation constant (Ka)
We will use the following expression.
Ka = [H⁺]² / Ca
Ka = 0.0158² / 0.086
Ka = 2.90 × 10⁻³
Which of these are not true statements a compound?
A compound's properties are usually not the same as the properties of the elements that make it up.
A compound always has the same composition.
A compound is made up of more than one type of atom.
A compound can have more than one chemical formula and still be considered the same compound.
Answer:
A compound can have more than one chemical formula and still be considered the same compound.
Explanation:
Which of these are not true statements a compound?
A compound's properties are usually not the same as the properties of the elements that make it up. TRUE. For instance, the salt NaCl has different properties than the solid metal Na and the gaseous nonmetal Cl₂.
A compound always has the same composition. TRUE. The ratio of elements in a compound is constant.
A compound is made up of more than one type of atom. TRUE. Unlike elements, compounds are formed by 2 or more elements.
A compound can have more than one chemical formula and still be considered the same compound. FALSE. Each compound can have only one chemical formula.
Why did UTF-8 replace the ASCII character-encoding standard?
Answer:
The UTF-8 replaced ASCII because it contained more characters than ASCII that is limited to 128 characters.
Explanation:
Both ASCII UTF-8 are used for encoding characters in computer communication. UTF-8 was favored over ASCII because it provided more characters than is available in ASCII making it more acceptable world over. Also, UTF-8 can be used for many different alphabets from around the world unlike ASCII which is limited to only languages that use the Latin Alphabet.
Unicode characters are encoded into 8 bit byte sequence by UTF-8
The reason why UTF-8 replaces ASCII character-encoding standard is due to the advantages, broader scope, and utility of UTF-8 compared to ASCII, which includes;
UTF-8, which is a Unicode-based encoding, has the capacity to support data based on a very wide variety of languages, including the ability for multilingual form and page accommodation. Based of the capabilities of UTF-8, server side logic required for character encoding determination is not requiredThe UTF-8 has the capacity for storing characters in more than one byte, which opens up the possibility for a wide range of characters including the ASCII characters and emojiDue to the above mentioned advantages, the UTF-8 is the preferred character encoding for a wider variety of user, making it to replace the ASCII
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Explain the difference between mass and weight and how they are measured.
Answer:
Mass:
1) Definition : Mass is the quantity of matter possessed by the body.
2) Quantity : Mass is a scalar quantity
3) Measurement: Mass is measured by ordinary balance
4) Unit : Unit of mass is kilograms in SI units.
5) Formula : m = W/g
Weight:
1) Definition: The gravitational force of attraction is called weight.
2) Quantity : Weight is a vector quantity.
3) Measurement : It is measured by spring balance
4) Unit : Unit of Weight is Newton in SI units.
5) Formula : W = mg [Where m is mass and g is acceleration due to gravity]
Answer:
Mass is how big an item is while weight is how heavy or light an item is. The mass of a human stays the same weather on Earth or on the Moon. While weight will be different on the Moon rather than on Earth.
Explanation:
Calculate the molar mass of calcium hydroxide, Ca(OH),(s). Write your answer using
proper units. Show all work.
Answer:
57.09 g/mol
Explanation:
Step 1: Find the mass for every 1 mole in each element
Ca - 40.08 g/mol
O - 16.00 g/mol
H - 1.01 g/mol
Step 2: Add the masses to find total mass
40.08 + 16.00 + 1.01 = 57.09 g/mol
So we have 57.09 grams per every mole in Calcium Hydroxide.
A sample of nitrogen gas is confined to a 14.0 L container at 375 torr and 37.0°C. How many moles of nitrogen are in the container?
Answer:
n = 0.271 moles
Explanation:
Given that,
Volume of container, V = 14 L
Pressure of Nitrogen gas, P = 375 torr
Temperature. T = 37°C=37+273=310°C
We need to find the number of moles of nitrogen in the container. Using gas equation,
PV = nRT
R is gas constant, R = 0.082 L-atm/mol-K
Since, 1 atm=760 torr
375 torr = 0.493 atm
Now,
[tex]n=\dfrac{PV}{RT}\\\\n=\dfrac{0.493\times 14}{0.082\times 310}\\\\n=0.271[/tex]
So, there are 0.271 moles of Nitrogen in the container.
The ideal gas law, also called the general gas equation, is the equation of the state of a hypothetical ideal gas.
The ideal gas law work under the constant:-
Pressure Temperature Volume
Hence the formula we gonna use is as follows:-
[tex]PV = nRT[/tex]
In the question, the pressure, temperature, and volume are given in two different systems.
As the date given in the question, after putting it into the equation:-
[tex]n= \frac{PV}{RT}[/tex]
[tex]n = \frac{0.493*14}{0.082 *310}[/tex]
n= 0.271.
The number of moles in the nitrogen container is 0.271.
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How many moles is 11 grams of H2O
Answer to the nearest 0.01 moles.
Answer:
hope your having a blessed day
Explanation:
Explanation:
We know :-
Molecular mass of H2O = 18 u
Molar mass = 18 g
Then no of moles = Mass given ÷ Molar mass
= 11 ÷ 18
= 0.611111..
or = 0.61
Which of the following nuclides will likely undergo a beta emission for its dominant radioactive decay mode?
a) yttrium-76
b) tin-105
c) cesium-120
d) barium-146
Answer:
barium-146
Explanation:
Beta emission is said to occur when a neutron is converted to a proton, an electron and a neutrino. Beta emission leads to a decrease in the Neutron/Proton ratio.
Beta emission is common for heavier nuclei having a large number of neutrons. Barium-146 has 90 neutrons, hence it is more likely to undergo beta emission than other nuclides stated among the options.
You need to make an aqueous solution of 0.237 M chromium(III) acetate for an experiment in lab, using a 500 mL volumetric flask. How much solid chromium(III) acetate should you add
Answer: 27.1 g of solid chromium(III) acetate should be added.
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.
[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]
where,
n = moles of solute
[tex]V_s[/tex] = volume of solution in ml
moles of [tex]Cr(CH_3COO)_3[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{xg}{229g/mol}[/tex]
Now put all the given values in the formula of molality, we get
[tex]0.237=\frac{xg\times 1000}{229g/mol\times 500ml}[/tex]
[tex]x=27.1[/tex]
Therefore, 27.1 g of solid chromium(III) acetate should be added.
Consider the diprotic acid H2A with K1 = 1.00 x 10-4 and K2 = 1.00 x 10-8 . Find the pH and concentrations of H2A, HA-, and A2- in (a) 0.100 M H2A; (b) 0.100 M NaHA; (c) 0.100 M Na2A
Answer:
Explanation:
H₂A ⇄ HA⁺ + A⁻
K₁ = [ HA⁺] [A⁻ ] / [ H₂A ]
HA⁺ ⇄ H⁺ + A⁻
K₂ = [ H⁺] [ A ⁻ ] / [ HA⁺ ]
H₂A ⇄ HA⁺ + A⁻
.100 0 0
.100 - C C C
K₁ = [ HA⁺] [A⁻ ] / [ H₂A ]
Putting the values
1.00 x 10⁻⁴ = C X C / .1 - C
10⁻⁵ - 10⁻⁴ C = C²
C² + 10⁻⁴ C - 10⁵ = 0
C = 8 X 10⁻² M
So concentration of H₂A that is [ H₂A ] = 1 - C = 0 .1 - 8 X 10⁻² M
= .02 = 2 x 10⁻² M
NaHA ⇄ Na⁺ + HA⁻
NaHA is a strong acidic salt so it will ionise 100 %
NaHA ⇄ Na⁺ + HA⁻
.1 .1 .1
concentration of HA⁻ = .1 M
Na₂A ⇄ 2Na⁺ + A⁻²
Na₂A is also a strongly ionic salt so it will dissociate 100 % .
Na₂A ⇄ 2Na⁺ + A⁻²
.1 .1 .1
concentration of A⁻² = .1 M
HA⁺ ⇄ H⁺ + A⁻
8 X 10⁻² C₁ C₁
K₂ = [ H⁺] [ A ⁻ ] / [ HA⁺ ]
Putting the values
1.00 x 10⁻⁸ = C₁ X C₁ / C
1.00 x 10⁻⁸ = C₁² / 8 X 10⁻²
C₁² = 8 x 10⁻¹⁰
C₁ = 2.828 x 10⁻¹⁰
[ H⁺] = 2.828 x 10⁻¹⁰
pH = - log [ H⁺] = - log 2.828 x 10⁻¹⁰
= 10 - log 2.828
= 10 - .45
= 9.55 .
Protons and Newton’s what is the difference?
The main difference between Proton, Neutron and Electrons can be found in their charges. Protons are positively charged and neutrons are neutral whereas electrons are negatively charged. Protons are found in the nucleus of the atom, and they reside together with neutrons. ... Protons are positively charged.
Two solutions, initially at 24.60 °C, are mixed in a coffee cup calorimeter (Ccal = 15.5 J/°C). When a 100.0 mL volume of 0.100 M AgNO3 solution is mixed with a 100.0 mL sample of 0.200 M NaCl solution, the temperature in the calorimeter rises to 25.30 °C. Determine the ∆H°rxn in kJ/mol AgCl for the reaction as written below. The density of the final solution is 1.00 g/mL and heat capacity of the final solution is 4.18 J/goC.
NaCl(aq) + AgNO3(aq) → AgCl(s) + NaNO3(aq) H°rxn= ?
Answer:
ΔH = -59.6kJ/mol
Explanation:
The reaction that occurs between Ag⁺ and Cl⁻ ions is:
Ag⁺ + Cl⁻ → AgCl(s) + ΔH
To find ΔH we need to obtain moles of reaction and heat released in the reaction because ΔH is defined as heat released per mole of reaction.
Moles of reaction:
Moles of Ag⁺ and Cl⁻ added are:
Ag⁺: 0.100L * (0.100mol / L) = 0.01moles
Cl⁻: 0.100L * (0.200mol / L) 0 0.02 moles
That means limiting reactant is Ag⁺ and moles of reaction are 0.01 moles
Heat released:
To find heat released we must use coffe cup calorimeter equation:
Q = C*m*ΔT
Where C is specific heat of solution (4.18J/g°C), m is the mass of solution (200g because there are 100 + 100mL = 200mL and density of solution is 1g/mL) and ΔT is change in temperature (25.30°C - 24.60°C = 0.70°C).
Replacing:
Q = C*m*ΔT
Q = 4.18J/g°C * 200g * 0.70°C
Q = 585,2J
Is total heat released.
The calorimeter absorbs:
15.5J / °C * 0.7°C = 10.85
Thus, when 0.01 moles reacts, 585.2J + 10.85 = 596.05J are released (Heat released is heat abosrbed by calorimeter + Heat absorbed by water) and ΔH is:
ΔH = 596.05J / 0.01 moles =
ΔH = 59605J / mol =
ΔH = -59.6kJ/molAs heat is released, ΔH < 0.
What fundamental unit of the metric system always has a prefix in front of it?
Answer:
Kilogram
Explanation:
The metric system is the Kilogram, meter, second system. These are fundamental quantities of the metric system.
Kilogram, the unit of mass always carries the prefix 'kilo' in its SI unit. Kilogram is the SI unit of mass. Hence, the fundamental unit on the metric system that always has a prefix in front of it is kilogram.
Round 54,752 to two significant figures
Answer:
55000 (put a line above the second 5)
how is nitrogen formed by valence bond theory?
The electronic configuration of ‘N’ atom is 2, 5 and to have Octet in the valence shell it requires three more electrons.When two nitrogen atoms approach each other, each atom contributes 3 electrons for bonding.There are six electrons shared between two nitrogen atoms in the form of three pairs.Therefore, there is a triple bond between two nitrogen atoms in $N _{ 2 }$ molecules.