Answer:
The correct answer is - 800.
Explanation:
Given:
Total amount = ? or assume x
spend in buying birthday item = 3/4 of x
given to sister = 1/5 of x
remaining to mother = 40
solution:
the remaning amount = x- (3x/4+x/5) = 4=
=> x- 19x/20 = 40
=> x = 20*40
=> x = 800
thus, the correct answer is = 800
Please help is for today
Answer:
Our bodies are designed to regulate our temperature. When it's cold outside, your body makes sure to keep the blood flowing to your core and vital organs to keep them warm. This can change the amount of blood flow to your hands and feet, making them feel cold
Share a family recipe for a cooking class- marking brainliest
Answer:
Sopes
In order to make them you will need
1.flour
2.Cheese
3.Lettuce
4. beans
5.tomatoe
Consider a buffer made by adding 132.8 g of NaC₇H₅O₂ to 300.0 mL of 1.17 M HC₇H₅O₂ (Ka = 6.3 x 10⁻⁵) What is the pH of this buffer?
Answer:
pH = 1.62
Explanation:
We can solve this problem using Henderson-Hasselbach's equation:
pH = pKa + log[tex]\frac{[A^-]}{[HA]}[/tex]Where
pKa = -log(Ka) = 4.20[A⁻] = [NaC₇H₅O₂][HA] = [HC₇H₅O₂]Now we convert 132.8 g of NaC₇H₅O₂ into moles, using its molar mass:
132.8 ÷ 144.11 g/mol = 0.921 molesThen we calculate [NaC₇H₅O₂]:
0.921 moles / 300.0 mL = 0.003 MNow we can proceed to calculate the pH of the solution:
pH = 4.20 + log[tex]\frac{0.003}{1.17}[/tex]pH = 1.62what is the difference between an acid and a base?
Answer:

A substance, mostly liquid that donates a proton or accepts an electron pair in reactions. An acid increases the concentration of H+ ions. A base is a substance that releases hydroxide (OH-) ions in aqueous solution, donates electrons and accepts protons.
[tex]{\underline{\underline{\bf{\red{\:\:Acid\:\:}}}}}[/tex]
Proton donor and electron pair acceptorIt can increase the concentration of H+ ion in aq. solution.pH value is <7Turn blue litmus paper into redAcid reacts with bases to form saltsAcid taste sour[tex]{\underline{\underline{\bf{\orange{\:\:Base\:\:}}}}}[/tex]
Proton acceptor and electron pair donorIt can increase the concentration of OH- ion in aq. solution.pH value is >7Turn red litmus paper into blueBases reacts with acids to form saltsBases taste soapyThe temperature of 100. g of water at 25.0C increases to 31.9C. How much energy was added to the water? The specific heat of water is 4.184J/gC.
Answer:
2890j
Explanation:
What was the purpose of letting the transformed cells sit in LB for a few minutes before spreading them onto the plates?
A. This allows time for the cells to express the antibiotic resistance gene
B. This allows the cells to take up the plasmid after the heat shock procedure
C. This allows time for the cells to warm up before plating
D. This allows cells time to start glowing green
Answer: D
Explanation:
1. Given the following unbalanced equation:
Al(SO3)3 + NaOH
---> Na2SO3 + Al(OH)3
If you start with 389.4 grams of Al(SO3)3 and 200 grams of NaOH ?
Identify the limiting reactant:
Identify the reactant in excess and by how much:
How many grams of Na2SO, will be produced:
If you perform the same reaction but get 212.4 grams of Na2SO3, what is
your percent yield?
Answer:
Limting reactant: NaOH
Excess reactant: Al₂(SO₃)₃ by 104.9 grams.
315 g of Na₂SO₃ are produced in the reaction
67.4 % is the percent yield.
Explanation:
Balaced equation is:
Al₂(SO₃)₃ + 6NaOH → 3Na₂SO₃ + 2Al(OH)₃
We convert the mass of each reactant to moles, to identify the limiting reactant:
389.4 g . 1mol/ 342.15g = 1.14 moles of sulfite
200 g . 1mol / 40g = 5 moles
1 mol of aluminum sulfite react to 6 moles of NaOH, according to stoichiometry.
If we have 1.14 moles of sulfite, we need (1.14 . 6)/1 = 6.82 moles
We only have 5 mol of NaOH, so this is the limiting reactant.
Then the aluminum sulfite is the excess.
6 moles of NaOH react to 1 mol of sulfite
Then, 5 moles of NaOH may react to (5 . 1)/6 = 0.83 moles.
1.14 mol - 0.83 mol = 0.31 moles remains after the reaction goes complete.
We convert to mass: 0.31 mol . 342.15g/mol = 104.9 g
Then, we work with the limiting reactant. Stoichiometry is 6:3 (2)
6 moles of NaOH can produce 3 moles of sodium sulfite
Then 5 moles will produce (5 . 3)/6 = 2.5 moles
We convert moles to mass: 2.5 mol . 126 g/mol = 315 g.
Percent yield = (Yield produced/Thoeretical yield) . 100
Percent yield = (212.4g /315g) . 100 = 67.4 %
What is the vapor pressure of an aqueous solution that has a solute mole fraction of 0.1000? The vapor pressure of water is 25.756 mmHg at 25 °C.
Answer:
χsolvent = 1.0000 - 0.1000 = 0.9000
Use Raoult's Law:
Psolution = (χsolvent) (P°solvent)
x = (0.900) (25.756)
x = 23.18 mmHg (to four sig figs)
The vapor pressure of an aqueous solution is x = 23.18 mmHg (to four sig figs)
χsolvent = 1.0000 - 0.1000 = 0.9000
Use Raoult's Law:
P solution = (χsolvent) (P°solvent)
x = (0.900) (25.756)
x = 23.18 mmHg (to four sig figs)
What is an aqueous solution?An aqueous answer is one in which the solvent is liquid water. that is, solute (dissolved) ions and molecules are surrounded by water molecules and integrated into the network of bonds within the water. The dissolved species then spread in the course of the water.
A solution wherein water is the solvent is called an aqueous solution. although water is an exceptional solvent, now not the whole thing dissolves comfortably in the water.
Aqueous' in a chemical equation suggests that the cloth dispersed in water (an answer in water). As an example, when we pour sodium hydroxide answer into dilute hydrochloric acid, we get an aqueous solution of sodium chloride. The liquid is used to signify the formation of liquid materials in response.
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#SPJ2
In what direction does thermal energy transfer?
Answer:
Either direction
Explanation:
If you cook food it would go from cold to hot. If you were to put a drink in the fridge it would go from hot to cold. So it is either direction.
7. Which object is excellent at holding onto electrons?
Answer:
Insulator
Explanation:
How does static electricity forma force field around an object?
Answer:
because its electrified and it like makes it own force feild
Why are diamonds unevenly distributed on Earth?
Soil forms only in places where rock particles are deposited.
Soil forms only in places where larger rocks are broken into smaller rocks.
Soil forms only within the Earth under heavy pressure.
Soil forms in the air and is then deposited mainly in places that get a lot of rain.
Answer:
Why aren't diamonds found evenly distributed on Earth? Diamonds are only formed under specific conditions that involve geological processes, such as volcanic activities and plate movements. Since these conditions and processes only take place in certain areas, you can only find diamonds in these special places.
Explanation:
What is the name of the compound Cd(MnO4)2?
A
cadmium manganate
B.
cadmium manganite
C.
cadmium permanganate
O
D.
admium permanganite
PLZ HELP ME ASAP!!!!(I WILL ALSO MARK BRAINLIEST!!!)
(True or False) A cold front often signals sunny warm weather.
Learning Task 3: Choose the letter of the correct answer to complete the
statement. Write your answer on your notebook.
a.
1.
is the oldest form where an image is transferred from
one surface to another.
a. Painting
b. Drawing
C. Printmaking
2. Screen frame commonly made of
covered tightly with
a mesh.
Wood
b. Plastic
C. Paper
3.
technique makes use of woven mesh to support an ink-
blocking stencil
a. Silkscreen printing
b. Intaglio printing
c. Photo emulsion printing
4 .
A tool that usually made of vinyl or rubber blade is called
a. Mesh
b. Squeegee
C. Emulsion
The oldest form where an image is transferred from one surface to another is printmaking, Screen frame commonly made of covered tightly with wood, technique makes use of woven mesh to support an ink blocking stencil is Silkscreen printing and A tool that usually made of vinyl or rubber blade is called Squeegee.
What is art?Art is a technique in which we use different kinds of things like paintings, printings, drawings and do exhibition for the decoration purpose.
Print is the oldest art form where an image is transferred from one surface to another surface by applying liquid material on one surface and get the print of that on another surface.Screen frames are generally about 70% of the content of wood material.Silk screen painting is used to transfer ink onto a object, leaving areas made impermeable to the ink by a blocking stencil.In the squeegee paintings, a scrapping implement is used which is made up of rubber blade and vinyl and known as squeegee.Hence C, A, A and B is the correct answers of the given questions.
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Iron is obtained by reaction of hematite (Fe2O3) with carbon monoxide. From the balanced reaction below, how many grams of iron is produced when 24.6 mol of hematite is used up in the reaction?
Fe2O3 + 3CO ® 2Fe + 3CO2
Answer: 2755.2 g of [tex]Fe[/tex] will be produced from 24.6 mol of haematite.
Explanation:
The balanced chemical equation is:
[tex]Fe_2O_3+3CO\rightarrow 2Fe+3CO_2[/tex]
According to stoichiometry :
1 mole of [tex]Fe_2O_3[/tex] produce = 2 moles of [tex]Fe[/tex]
Thus 24.6 moles of [tex]Fe_2O_3[/tex] will produce=[tex]\frac{2}{1}\times 24.6=49.2moles[/tex] of [tex]Fe[/tex]
Mass of [tex]Fe=moles\times {\text {Molar mass}}=49.2moles\times 56g/mol=2755.2g[/tex]
Thus 2755.2 g of [tex]Fe[/tex] will be produced from 24.6 mol of haematite.
A weather balloon has a volume of 200.0 L at a pressure of 760 mm Hg. As it rises, the pressure decreases to 282 mm Hg.
a. Will the volume of the balloon increase or decrease? Why?
b. What is the new volume of the balloon? (Assume constant temperature)
Answer:
a. Increase
b. 539 L
Explanation:
Step 1: Given data
Initial volume (V₁): 200.0 LInitial pressure (P₁): 760 mmHgFinal volume (V₂): ?Final pressure (P₂): 282 mmHgStep 2: Calculate the final volume of the gas
The pressure of the gas is inversely proportional to the volume. So, as the pressure decreases, the volume must increase. Assuming constant temperature and ideal behavior, we can calculate the final volume of the gas using Boyle's law.
P₁ × V₁ = P₂ × V₂
V₂ = P₁ × V₁/P₂
V₂ = 760 mmHg × 200.0 L/282 mmHg = 539 L
A sample of nitrogen gas is stored in a 0.500 L flask at 101.3 atm. The gas is transferred to a 0.750
L flask. What is the pressure of nitrogen in the second flask if the temperature remains constant?
Answer:
67.5 atm
Explanation:
To answer this problem we can use Boyle's law, which states that at constant temperature the pressure and volume of a gas can be described as:
P₁V₁=P₂V₂
In this case:
P₁ = 101.3 atm
V₁ = 0.500 L
P₂ = ?
V₂ = 0.750 L
We input the data:
101.3 atm * 0.500 L = P₂ * 0.750 L
And solve for P₂:
P₂ = 67.5 atm
12. How many moles of atoms are present in 154 g of Na2O?
A) 2.48 mol
B) 7.45 mol
C) 51.3 mol
D) 0.827 mol
Answer:
[tex]\boxed {\boxed {\sf A. \ 2.48 \ mol \ Na_2O}}[/tex]
Explanation:
We are asked to convert an amount in grams to moles. To do this, we use the molar mass. This is the number of grams in one mole of a substance. It is the same value numerically as the atomic mass on the Periodic Table, however the units are grams per mole, not atomic mass units.
Look up the molar masses for the individual elements.
Sodium (Na): 22.9897693 g/mol Oxygen (O): 15.999 g/molLook back at the formula: Na₂O. Notice there is a subscript of 2 after sodium. This means there are 2 atoms of sodium in every molecule, so we have to multiply sodium's molar mass by 2 before adding oxygen's.
Na₂O: 2(22.9897693 g/mol)+ 15.999 g/mol = 61.9785386 g/molSet up a ratio using the molar mass.
[tex]\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}[/tex]
Multiply by the given number of grams.
[tex]154 \ g \ Na_2O*\frac {61.9785386 \ g \ Na_2O}{1 \ mol \ Na_2O}[/tex]
Flip the ratio so the grams of sodium oxide can cancel each other out.
[tex]154 \ g \ Na_2O*\frac {1 \ mol \ Na_2O}{61.9785386 \ g \ Na_2O}[/tex]
[tex]154 *\frac {1 \ mol \ Na_2O}{61.9785386 }[/tex]
[tex]\frac {154}{61.9785386 } \ mol \ Na_2O[/tex]
[tex]2.48473106141 \ mol \ Na_2O[/tex]
The original measurement of grams given has 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place.
2.48473106141The 4 in the thousandth place tells us to leave the 8.
[tex]2.48 \ mol \ Na_2O[/tex]
There are 2.48 moles of sodium oxide in 154 grams, so choice A is correct.
What would happen to the moon’s interia were to increase? A the moon will fly into space. B the moon will smash into Earth. C the moon will smash into pluto.
Answer:
B
Explanation:
How saliva works as a buffering agent?
Answer:
The carbonic acid/bicarbonate buffer is the major buffer in stimulated saliva, with bicarbonate acting mainly to neutralize acids produced by bacteria when they digest sugars in the mouth or acids from the stomach. The concentration of the bicarbonate ion depends largely on the salivary flow rate.
Explanation:
Basta Yan sagut ko eh
Answer:
The carbonic acid/bicarbonate buffer is the major buffer in stimulated saliva, with bicarbonate acting mainly to neutralize acids produced by bacteria when they digest sugars in the mouth or acids from the stomach. The concentration of the bicarbonate ion depends largely on the salivary flow rate
Explanation:
lave
Use the drop-down menus to identify the parts of a
wave.
A
B:
C
D
Answer:
Use the drop-down menus to make your selections.
What is the difference between wave A and wave B?
✔ Wave A has higher amplitude than wave B.
What is the difference between wave C and wave D?
✔ Wave C has a lower frequency than wave D.
Explanation:
According to the Kinetic Molecular Theory, which container has helium particles with the greatest average kinetic energy?
Answer:
Explanation:
The correct option would be that the average kinetic energy of the gas particles is greater in container B because it has a higher temperature.
According to the kinetic theory of matter, the temperate of a substance is a measure of the average kinetic energy of the molecules of substance. In other words, the higher the temperature of a substance, the higher the average kinetic energy of the molecules of the substance.
In the illustration, the gas in container B showed a higher temperature than that of container A as indicated on the thermometer, it thus means that the average kinetic energy of the molecules of gas B is higher than those of gas A.
Identify the term that matches each definition.
a. A characteristic that describes substances that evaporate readily, producing large amounts of vapors _________
b. The front vent of a fume hood, which helps maintain proper air circulation ___________
c. The glass panel in front of the fume hood that shields the user from fumes and other hazards ___________
d. The horizontal, flat area of a fume hood upon which experiments are carried out ________
Answer:
a. Volatile.
b. Air foil.
c. Sash.
d. Work surface.
Explanation:
In science, matter can be defined as anything that has mass and occupies space. Any physical object that is found on earth is typically composed of matter. Matter are known to be made up of atoms and as a result has the property of existing in states.
Generally, matter exists in three (3) distinct or classical phases and these are;
I. Solid.
II. Liquid.
III. Gas.
Matching the terms with their respective definition, we have;
a. Volatile: A characteristic that describes substances that evaporate readily, producing large amounts of vapors.
b. Air foil: the front vent of a fume hood, which helps maintain proper air circulation.
c. Sash: the glass panel in front of the fume hood that shields the user from fumes and other hazards.
d. Work surface: the horizontal, flat area of a fume hood upon which experiments are carried out.
How many moles of argon, Ar, are in 1.31×1024 Ar atoms?
Answer:
2.18 mol Ar.
Explanation:
Hello there!
In this case, according to the definition of mole as the amount of particles of a given substance, it is possible to introduce the Avogadro's number to assert that 1 mole of any element contains 6.022x10²³ atoms; thus, the moles of Ar in the given amount of atoms turns out to be:
[tex]1.31x10^{24}Ar atoms*\frac{1molAr}{6.022x10^{23}atoms}\\\\=2.18molAr[/tex]
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What do we call a large group of wind turbines used to generate electricity?
1)Wind Pack
2)Wind Mill
3) Wind Farm
4) Wind Plant
Answer:
your answer is 3 hope this helps you
Answer:
A wind farm
Explanation:
another word is a wind park
Match each definition to the appropriate term.
Sum of the internal energy plus the product of the pressure and volume for a reaction
The extent of randomness in a system
The condition that a reaction takes place without outside help
Difference of the enthalpy (of a system) minus the product of the entropy and absolute temperature
Solution in which no more solute can be dissolved in the solvent
Answer:
Enthalpy, Entropy, Spontaneity, Gibbs free energy, saturated solution
Explanation:
Enthalpy is defined as the heat released or the heat absorbed during the process at a constant pressure which is equal to the Enthalpy shift. Enthalpy is also called as heat content and it is the sum total of internal energy and the product of the volume and pressure of a system.
Entropy is defined as the measure of randomness of a system or the disorder of the system.
Spontaneity is defined as the condition of being spontaneous. It is the condition where a reaction takes place without any help from outside.
Gibbs free energy is defined as the energy that is used to quantify the maximum work done in a thermodynamic system at constant temperature and pressure. It is the also known as the Gibbs energy or function.
Saturated solution is defined as the solution where the maximum amount of the dissolved solute is present in the solvent. In case of a saturated solution, the extra solute does not dissolve. In order words, it is a solution where no more solute can dissolved in solvent.
The sum of the internal energy plus the product of the pressure and volume for a reaction represents Enthalpy , Entropy is the extent of randomness in a system, Spontaneity is that condition that a reaction takes place without outside help, Gibb's free energy is the difference of the enthalpy (of a system) minus the product of the entropy and absolute temperature and Saturated solution in which no more solute can be dissolved in the solvent.
Which properties will define chemical reaction?Thermodynamically chemical reactions will be define by considering the properties like entropy, enthalpy, free energy, internal energy, temperature and many more.
Enthalpy of the reaction tells about the total amount of heat released or absorbed during a chemical reaction, and it is calculated as sum of the internal energy plus the product of the pressure and volume for a reaction.Entropy of any reaction tells about the randomness and uncertainty present within the molecule or atoms.Spontaneity of any chemical reaction tells about the ease of completion of that reaction. Gibb's free energy is the total energy involved in that reaction and represented as difference of the enthalpy (of a system) minus the product of the entropy and absolute temperature.Saturated solutions are those solutions in which all solute get completely dissolved, no solute will remain undissolved.Hence correct answers are Enthalpy , Entropy ,Spontaneity, Gibb's free energy and Saturated solutions.
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How long did it take to get the Hubble Telescope into space?
Which of the following is a primary source for scientific information? O A. Doctoral theses OB. A handbook of scientific facts O C. Reviews of scientific studies D. Public opinion about a scientific issue
what is independent variable
Answer:
a variable (often denoted by x ) whose variation does not depend on that of another.
Explanation:
You can think of independent and dependent variables in terms of cause and effect: an independent variable is the variable you think is the cause, while a dependent variable is the effect. In an experiment, you manipulate the independent variable and measure the outcome in the dependent variable.For example, someone's age might be an independent variable. Other factors (such as what they eat, how much they go to school, how much television they watch) aren't going to change a person's age.