Answer:
42.857 seconds
Explanation:
Given that:
The average adult heart pumps about 84./mLs of blood at 72 beats per minute.
The total volume = 3600 mL
The objective is to calculate how long it would take the average heart circulate 3600 mL of blood.
Since 84 mL of blood takes 1 seconds to pump,
assuming q is the time required for heart to pump 3600 mL of blood
[tex]Time \ ( q )= \dfrac{3600 mL \times 1\ seconds}{84 \ mL}[/tex]
TIme (q) = 42.857 seconds
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
How do you determine the chemical reactivity for metals by using the periodic table?
Answer:
Chemical reactivity increases down a group and decreases from left to right of a period.
Explanation:
The higher the ionization energy is, the lower the reactivity is. Since the ionization energy is highest in the top right corner of the periodic table, we can assume that the most reactive elements are in the opposite bottom left corner. This is because the electrons that react are farther away from the nucleus thus experience less attraction to the nucleus (called nuclear shielding). Therefore their electrons are more easily removed than elements that don't ecperience nuclear shielding.
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.
The six metals have the work functions, E0.A. Rank these metals on the basis of their cutoff frequency.B. Rank these metals on the basis of the maximum wavelength of light needed to free electrons from their surface. C. Each metal is illuminated with 400 nm (3.10 eV) light. Rank the metals on the basis of the maximum kinetic energy of the emitted electrons.1. Cesium: w = 2.1 eV 2. Aliminium: w = 4.1 eV 3. Beryllium: w = 5.0 eV 4. Potassium: w = 2.3 eV 5. Platinium: w = 6.4 eV 6. Magnesium: w = 3.7 eV
Answer:
a) Platinum > Beryllium > Aluminum > Magnesium > Potassium > Cesium
b) Cesium > Potassium > Magnesium > Aluminum > Beryllium > Platinum
c) Cesium > Potassium
Explanation:
We must recall that the frequency of an electromagnetic wave is directly proportional to its energy. Hence as the work function of the metal increases, the minimum frequency required for emission of electrons occur increases accordingly.
Similarly, the maximum wavelength required for electron emission to occur varies inversely as the work function of the metal hence the answer provided.
Lastly, only caesium and potassium has work function less than the energy of the incident photon hence only these two metals experience electron emission with the kinetic energy of electrons emitted from caesium greater than that emitted from potassium.
The density of gold is 19.3 g/cm3. What is the volume of a 13 g gold nugget? (Density: D = ) .25 cm3 .67 cm3 1.48 cm3 2.50 cm3
Answer:
The answer is 0.67 cm³Explanation:
Density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]Making volume the subject we have
[tex]volume = \frac{mass}{Density} [/tex]From the question
mass of gold nugget = 13 g
Density = 19.3 g/cm³
Substitute the values into the above formula and solve for the volume
We have
[tex]volume = \frac{13}{19.3} [/tex]= 0.673575
We have the final answer as
0.67 cm³Hope this helps you
Answer:
0.674
Explanation:
Ammonium perchlorate is the solid rocket fuel used by the U.S. Space Shuttle. It reacts with itself to produce nitrogen gas , chlorine gas , oxygen gas , water , and a great deal of energy.
What mass of water is produced by the reaction of of ammonium perchlorate?
Answer:
2.9 g
Explanation:
There is some info missing. I think this is the original question.
Ammonium perchlorate is the solid rocket fuel used by the U.S. Space Shuttle. It reacts with itself to produce nitrogen gas, chlorine gas, oxygen gas, water, and a great deal of energy.
What mass of water is produced by the reaction of 9.6 g of ammonium perchlorate?
Step 1: Given data
Mass of ammonium perchlorate: 9.6 g
Step 2: Write the balanced equation
2 NH₄ClO₄(s) → N₂(g) + Cl₂(g) + 2 O₂(g) + 4 H₂O(l)
Step 3: Calculate the moles corresponding to 9.6 g of ammonium perchlorate
The molar mass of ammonium perchlorate is 117.49 g/mol.
[tex]9.6 g \times \frac{1mol}{117.49 g} = 0.082mol[/tex]
Step 4: Calculate the moles of water formed from 0.082 moles of ammonium perchlorate
The molar ratio of NH₄ClO₄ to H₂O is 2:4. The moles of water formed are 4/2 × 0.082 mol = 0.16 mol
Step 5: Calculate the mass corresponding to 0.16 moles of water
The molar mass of water is 18.02 g/mol.
[tex]0.16 mol \times \frac{18.02g}{mol} = 2.9 g[/tex]
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:
which statement describes a risk of technological design of headphones?
Answer: maybe a choking hazard for the ones with wires
Explanation:
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
Question: How will soap or alcohol affect the hydrogen bonds between different water molecules? Hypothesis: Materials: Penny, water, soap, pipette, paper towel, 70% rubbing alcohol
Answer:
A soap or alcohol will interfere with the hydrogen bonding between water molecules making it weaker
Explanation:
A water molecule is polar as the oxygen atom is strongly electronegative and draws the electrons it shares with the hydrogen atoms in the water molecule to itself. This creates a partial negative charge on the oxygen atom and partial positive charges on the hydrogen atoms. The attraction of neighboring oxygen to hydrogen atoms in a water molecule results in hydrogen bonding.
However, a detergent molecule which has a polar head and a hydrophobic tail, when added to water significantly interferes with the hydrogen bonding between water molecules. The polar head is attracted to water molecules whereas the hydrophobic tail of each molecule are not. The detergent molecules form clusters known as micelles with the polar heads attracted to water and the hydrophobic tails directed towards the center of the micelle, away from water molecules. This weakens the hydrogen bonding between water molecules
An alcohol contains a polar -OH group in its molecules. However, the hydrogen bonding between alcohol molecules are weaker than that in water because the other end of the alcohol molecule has a C-O bond which is less polar than the O-H bond. Therefore, when an alcohol is added to water, it weakens the hydrogen bonding in water.
This weakening of the hydrogen bonding in water also has the effect of lowering the surface tension of water.
When alcohol is added to water, it disrupts the hydrogen bonding network between water molecules. Alcohol molecules compete with water molecules for hydrogen bonding sites, leading to a decrease in the number and strength of hydrogen bonds between water molecules.
When soap is added to water, the hydrophobic tails of the soap molecules are attracted to each other, forming structures called micelles.
Alcohol, such as rubbing alcohol (isopropyl alcohol), is a different type of molecule compared to soap.
Experiment with a penny, water, soap, and rubbing alcohol, the soap is likely to disrupt the hydrogen bonds more significantly than rubbing alcohol. Soap will interfere with the hydrogen bonding between water molecules through micelle formation and reduction of surface tension.
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A crystalline form of solid fat is ?
_ _ _ _ _ _ _ _ _ _
( 10 letter word )
A crystalline form of solid fat is Glycerides
Hope it helped :)
Given the values for C (2.5) and O (3.5), calculate the electronegativity difference in a carbon monoxide bond, CO
Answer:
ΔEN CO = 1.0
Explanation:
To calculate the electronegativity difference, we have to substract the element which has the highest EN to the other, that has a low value.
For this case EN from O - EN from C
Electronegativity is a property of the periodic table that increases diagonally, where Fr and Rb are the elements of less EN while F is the most electronegative element, with a value of 4. This is because F is an element with a high ionization energy and a negative electronic affinity.
ΔEN CO = 3.5 - 2.5 = 1.0
Electronegativity (EN) describes the ability of an atom to compete for
electrons with other atoms to which it is attached.
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.
Why is 1,2-dichloroethane a better solvent for caffeine extraction than water?
Answer:
Answer is in the explanation
Explanation:
In an extraction process, you want to take the higher amount of a compound. You can make this due solubility of the compound in a particular solvent.
The higher solubility of the compound in the solvent, the higher extraction of the compound from the original mixture.
Solubility of caffeine in water is about 16mg/mL in water at room temperature. But in 1,2-dichloroethane is about 100mg/mL.
Thus, the reason of the better extraction with 1,2-dichloroethane is because of the high solubility of caffeine in this solvent.
The reason for 1,2 dichloroethane a better solvent should be explained below.
Why is 1,2-dichloroethane a better solvent for caffeine extraction as compared to water?In the case of the extraction process, Here we considered the greater amount of a compound. The higher solubility of the compound should be in the solvent, the higher extraction of the compound should be from the original mixture.
Thus, it should be better due to the high solubility of caffeine in this solvent.
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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
Round 54,752 to two significant figures
Answer:
55000 (put a line above the second 5)
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
A solution has a hydroxide-ion concentration of 0.0040 M. What is the pOH of the solution? A solution has a pH value of 3.66. What is the pOH for this solution? What is the pH of a 0.0072 M hydrochloric acid solution?
Answer:
1. pOH = 2.4
2. pOH = 10.34
3. pH = 2.14
Explanation:
1. Determination of the pOH.
Concentration of Hydroxide ion, [OH-] = 0.004 M
pOH =?
pOH = - log [OH-]
pOH = - log (0.004)
pOH = 2.4
Therefore, the pOH of the solution is 2.4
2. Determination of the pOH.
pH = 3.66
pOH =?
pH and pOH are related by the following equation:
pH + pOH = 14
With the above formula, we can obtain the pOH of the solution as follow:
pH = 3.66
pOH =?
pH + pOH = 14
3.66 + pOH = 14
Collect like terms
pOH = 14 - 3.66
pOH = 10.34
Therefore, the pOH of the solution is 10.34
3. Determination of the pH.
Molarity of HCl = 0.0072 M
Concentration of Hydrogen ion, [H+] =?
Thus, we can obtain the concentration of Hydrogen ion, [H+] as follow:
HCl(aq) —> H+(aq) + Cl-(aq)
From the balanced equation above,
1 mole of HCl produced 1 mole of H+.
Therefore, 0.0072 M HCl will also produce 0.0072 M H+.
Therefore, the concentration of Hydrogen ion, [H+] in the solution is 0.0072 M.
Finally, we shall determine the pH of the solution as follow:
Concentration of Hydrogen ion, [H+] = 0.0072 M.
pH =?
pH = - log [H+]
pH = - log (0.0072)
pH = 2.14
Therefore, the pH of the solution is 2.14
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:
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
What must happen to uranium before it can be used as a fuel source?
Explanation:
Before it can be used in a reactor for electricity generation, however, it must undergo a series of processes to produce a useable fuel. For most of the world's reactors, the next step in making the fuel is to convert the uranium oxide into a gas, uranium hexafluoride (UF6), which enables it to be enriched.
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 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.
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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A piece of magnesium is put in a test tube containing hydrochloric acid. Explain the chemical reaction.
Answer:
The magnesium reacts with the acid, producing visible bubbles of hydrogen gas. (Optional) If the flame of a butane fireplace lighter is held above the bursting bubbles, they will produce audible pops as the hydrogen ignites. Magnesium ribbon is a flammable solid. Hydrochloric acid is a corrosive liquid.
Explanation:
Magnesium reacts with hydrochloric acid according to the equation: Mg(s) + 2 HCl(aq) --> MgCl2(aq) + H2(g) This demonstration can be used to illustrate the characteristic reaction of metals with acid, a single replacement reaction, or to demonstrate the generation of hydrogen gas.
The reaction between the magnesium metal and hydrochloric acid can be represented as:
[tex]Mg(s) + 2HCl(aq) \longrightarrow MgCl_2(aq) +H_2(g)[/tex]
How the reaction between Mg and HCl is a redox reaction?The chemical reaction between magnesium metal and dilute hydrochloric acid can be described as a redox reaction where both reduction and oxidation will take place.
The following chemical reaction Mg and HCl will take place as:
[tex]Mg(s) + 2HCl(aq) \longrightarrow MgCl_2(aq) +H_2(g)[/tex]
The oxidation state of Mg changes from 0 to +2, Mg is getting oxidized to magnesium cation, Mg²⁺ whereas the oxidation state of Hydrogen of HCl is changed from + 1 to 0 and is getting reduced.
Therefore, Magnesium acts as a reducing agent, and hydrogen acts as an oxidizing agent in this reaction. There is a formation of magnesium chloride and hydrogen gas is liberated.
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How many significant figures are in 0.003450?
Answer:
4
Explanation:
Four significant figures
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.
Unit Conversion Help Thank you
Answer : 1721.72 g/qt are in 18.2 g/cL
Explanation :
As we are given: 18.2 g/cL
Now we have to convert 18.2 g/cL to g/qt.
Conversions used are:
(1) 1 L = 100 cL
(2) 1 L = 1000 mL
(3) 1 qt = 946 qt
The conversion expression will be:
[tex]\frac{18.2g}{1cL}\times \frac{100cL}{1L}\times \frac{1L}{1000mL}\times \frac{946mL}{1qt}[/tex]
[tex]=1721.72\text{ g/qt}[/tex]
Therefore, 1721.72 g/qt are in 18.2 g/cL
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.