can someone at least help with one of these i will give brainliest
Answer:
1375 J/kg.°C
Explanation:
From the question First question,
Q = cm(Δt)................... Equation 1
Where Q = Heat released, c = specific heat capacity of the unknown metal, m = mass of the unknown metal, Δt = Change in temperature.
make c the subject of the equation
c = Q/mΔt.................. Equation 2
Given: Q = -5500 J (Since heat is released, Q is negative), m = 200 g = 0.2 kg, Δt = 10-30 = -20°C
Substitite these values into equation 2
c = -5500/[0.2×(-20)]
c = -5500/-4
c = 1375 J/kg.°C
a repelling force occurs between two charged objects when the charges are
Answer:
Like signs.
Explanation:
When two charges are like signs, a repelling force will occur.
Which statement describes particles of an ideal gas, based on the kinetic molecular theory?
Answer:
There are 5 steps/rules of the ideal gases based on kinetic theory.
Explanation:
1. Particles in a gas are constant moving in random motion.
2. combined volume of the particles is negligible.
3. particles exert no forces on one another
4. any collisions between the particles are completely elastic
5. the average kinetic energy of particles is proportional to temperature in kelvins.
(I had help explaining steps from Sal Khan. I hope this helps! Have a great day!)
The H-R diagram is useful in
studying all of these about a star
A.except for its brightness b.location in the sky c.temperature
D.magnitude
Answer:
b.location in the sky (If the question is saying:The H-R diagram is useful in
studying all of these about a star except for)
Explanation:
The theoretical HR diagram plots the temperature of the star vs their luminosity (brightness) and the observational HR diagram plots color of the stars vs the absolute magnitude. Depending on mass, stars will also go through specific evolutionary stages that can be seen through the location of the star on the HR diagram. However, the HR diagram will not have data on the location of the star in the sky.
Consider the titration of 82.0 mL of 0.140 M Ba(OH)2 by 0.560 M HCl. Calculate the pH of the resulting solution after the following volumes of HCl have been added. (a) 0.0 mL WebAssign will check your answer for the correct number of significant figures. 13.447 Correct: Your answer is correct. (b) 15.0 mL WebAssign will check your answer for the correct number of significant figures. 12.25 Incorrect: Your answer is incorrect.
Answer:
a) pH = 13.447
b) pH = 13.176
Explanation:
Ba (OH)₂ is a strong base and ionizes completely in solution to give barium amend hydroxide ions.
The equation of the dissociation of Ba(OH)₂ is given below:
Ba(OH)₂ ----> Ba2+ + 2OH-
1 mole of Ba(OH)₂ produces 2 Moles of OH- ions
a) Before the addition of HCl, i.e.,when 0.00 mL of HCl has been added;
Concentration of hydroxide ions, [OH-] = 0.140 x 2 = 0.a) [OH-] = 0.100 x 2 = 0.280
pOH = -log [OH-]
pOH = -log (0.280)
pOH = 0.553
pH = 14 - 0.553= 13.447
b) pH when 15.0 mL HCl has been added
Moles Ba(OH)₂ = concentration × volume
Volume of Ba(OH)₂ = 82.0 mL = 0.082 L, concentration = 0.140 M
moles of Ba(OH)₂ = 0.082 x 0.140 = 0.01148 moles
moles OH- produced by 0.01148 moles of Ba(OH)₂ = 2 x 0.01148= 0.02296
moles HCl = 0.0150 L x 0.560 = 0.0084
moles of H+ produced by 0.0084 HCl = 0.0084
0.0084 H+ willnreact with 0.0084 moles of OH-
moles OH- left after the reaction = 0.02296 - 0.0084 = 0.01456 moles
total volume of new solution = (82 +15) mL = 97 mL => 0.097 L
Concentration of OH- ions = moles / volume
[OH-] = 0.01456 / 0.097 = 0.1501
pOH = -log [OH-]
pOH = -log (0.150)
pOH = 0.824
pH = 14 - 0.824
pH = 13.176
Can someone help me with this. Thank you
Answer:
Location x is experiencing daytime because it is facing directly to the sun.
Explanation:
From a background understanding of the solar system, the side of the planet facing the sun will be experiencing daytime while the other side of the planet will be experiencing either partial or total darkness depending on the location.
From the diagram given above, we can see clearly that location x is facing the sun and as such, light rays from the sun lightens the location. When this happens, location x will be experiencing daytime.
In conclusion, location x is experiencing daytime because it is facing directly to the sun.
If it takes 25 mL of 0.05 M HCl to neutralize 345 mL of NaOH solution, what is the concentration, M, of the NaOH solution?
Answer:
400ml
Explanation:
In the reaction shown, 88.388.3 g salicylic acid, C7H6O3C7H6O3 , reacts with excess acetic anhydride, C4H6O3C4H6O3 , producing 62.062.0 g of aspirin, C9H8O4C9H8O4 . C7H6O3(s)+C4H6O3(l)⟶C9H8O4(s)+CH3CO2H(l) C7H6O3(s)+C4H6O3(l)⟶C9H8O4(s)+CH3CO2H(l) Calculate the percent yield of this reaction
Answer:
53.9%
Explanation:
The equation of the reaction is;
C4H6O3+C7H6O3→C9H8O4+C2H4O2
Number of moles of salicyclic acid reacted = 88.3 g/138.121 g/mol = 0.639 moles
1 mole of salicyclic acid yields 1 mole of aspirin
0.639 moles of salicyclic acid also yields 0.639 moles of asprin
Theoretical yield of asprin = 0.639 moles * 180.158 g/mol
Theoretical yield of asprin = 115.12 g
Percent yield = Actual yield/Theoretical yield * 100/1
Percent yield = 62.0 g/115.12 g * 100
Percent yield = 53.9%
Litmus turns
in acidic solutions.
green
yellow
blue
red
Answer:
red
Explanation:
red shows if solution is acidic
A woman weighing 600 N is leaning on the ground with shoe soles with a total area of 0.04 m2. Calculate the pressure of the motors
Answer:
1.5×10^4
Explanation:
Pressure= force/area
P= 600/0.04
P= 15000
P= 1.5×10^4
What is a flame test?
A. A method for determining the products of combustion
B. A method of obtaining an emission spectrum from a sample
C. A method for testing the flammability of a sample
D. A method for determining the temperature of combustion
SUBMIT
Answer:
B. A method of obtaining an emission spectrum from a sample
Explanation:
Flame test is a method of obtaining an emission spectrum from a sample.
Emission spectrum is defined as a spectrum of a chemical compound or substance composed of frequencies of electromagnetic radiation. Radiations which are emitted while electron make transition from higher to lower energy level.
Energy of photon is equal to the difference between the two energy states . There are many possible electronic transitions in an atom and every transition has a specific wavelength.Flame test is characteristic for each element as that of an emission spectrum.
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A sealed balloon occupies a volume of 250 mL at an unknown temperature. When the temperature is altered to 30 C, the balloon's volume becomes 0.5 L. Calculate the initial temperature of the air in the balloon.
Answer:
Initial temperature, T1 = 15°C
Explanation:
Given the following data;
Initial volume, V1 = 250 mL to Liters = 250/1000 = 0.25 L
Final temperature, T2 = 30°C
Final volume, V2 = 0.5 L
To find the initial temperature T1, we would use Charles' law.
Charles states that when the pressure of an ideal gas is kept constant, the volume of the gas is directly proportional to the absolute temperature of the gas.
Mathematically, Charles is given by;
[tex] \frac {V}{T} = K[/tex]
[tex] \frac{V1}{T1} = \frac{V2}{T2}[/tex]
Making T1 the subject of formula, we have;
[tex] T_{1}= \frac{V_{1}}{V_{2}} * T_{2}[/tex]
Substituting into the formula, we have;
[tex] T_{1}= \frac{0.25}{0.5} * 30[/tex]
[tex] T_{1}= 0.5 * 30 [/tex]
Initial temperature, T1 = 15°C
How many milliliters of 3.0 M H2SO4 are needed to make 450 mL of 0.10 M H2SO4?
how can a match light without a spark
Answer:
Use friction
Explanation:
Friction is the force that stops something in motion. It also heats up something, creating a gravitational heat! A match striked against the lighter will create a flame, because of friction :)
What happens when you change the number of protons keeping the numbers of other particles the same?
Answer:
See explanation
Explanation:
The atomic number refers to the number of protons in the nucleus of an atom. We identify an element by its atomic number.
When the atomic number of an atom of an element is changed, we have changed the identity of that atom and transformed it into an atom of a different element.
For example, if we add a proton to a sodium atom, we create a magnesium atom. If we remove a proton from a sodium atom, we create a neon atom.
Which of the following statements best defines the theoretical yield of a reaction?
a) The ratio of measured yield over actual yield
b) The amount of product measured after a reaction
c) The ratio of measured yield over stoichiometric yield
d)The maximum amount of product that can be obtained
The statement which best defines the theoretical yield of a reaction is the maximum amount of product that can be obtained.
What is yield of any reaction?Yield of any chemical reaction gives idea about the amount of product that will be produced by the chemical reaction between reactants.
Theoretical yield gives idea about the how much maximum yield of any product will be produced in the given chemical reaction by using the stoichiometry of the reaction.
Hence theoretical yield is the maximum amount of product that can be obtained.
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_______ in saliva start the chemical digestion process
Answer:
amylase
Explanation:
the transfer of thermal energy that causes a metal spoon in hot liquid to get hot.
Answer:
Conduction
Explanation:
Conduction can be regarded as transfer of thermal energy which exist
between two or more objects that are in contact with each other. From the question, the spoon touches the hot liquid and heat is transferred to the spoon through conduction
THIS IS FOR SCIENCE PLS HELP ME WRITE MY PROMPT How does the human population and human activity affect Earth?
Add distilled water to the beaker until the volume
totals 15 mL.
Record the amount of cornstarch that dissolved.
all
about half
none
20
25 ml
15
10
5
Intro
Answer:
The correct answer on edge for 2021 is C. None.
Explanation:
We know this is correct because the solution is heterogenous after it has been stirred: the substance is not soluble in water.
The solution is heterogeneous after it has been stirred. The cornstarch is not soluble in water. Therefore, option C is correct.
What is the solution?Any mixture of one or more solutes that have been dissolved in a solvent is referred to as a solution. To create a homogenous mixture, a solute must dissolve in a solvent. To create a homogenous mixture, a solute must dissolve in a solvent.
Whereas homogenous mixtures seem consistent throughout, heterogeneous mixtures have clearly discernible components. A solution, which can be a solid, liquid, or gas, is the most typical kind of homogenous mixture.
No matter how you sample a homogenous solution, it often has the same characteristics. Sources of water, saline solution, certain metals, and bitumen are homogenous mixes. Examples of heterogeneous combinations are chicken noodle soup, sand, and oil, and water.
Thus, option C is correct.
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litmus is made from plant pigment.
it is red when placed in an acidic solution.
it is blue when placed in an alkaline solution.
it is purple when neutral.
a) what do we call substance that change colour like this?
b) what colour would litmus be in a solution of pH 10?
c) what colour would you expect litmus to be in pure water?
Answer:
For (a): The substances are known as acids and bases.
For (b): The color of the litmus for pH = 10 will be blue.
For (c): The color of the litmus for pure water will be purple.
Explanation:
pH determines the acidity or basicity of a solution. There are three types of solution classified based on the pH:
If pH<7 then the solution is acidic in nature If pH>7 then the solution is basic/alkaline in nature If pH=7 then the solution is neutral in natureLitmus paper is used as an indicator to know the type of solution. There are 2 types of litmus paper:
Red litmus paper: It turns blue when placed in a basic/alkaline solution.Blue litmus paper: It turns red when placed in an acidic solution.(a):
An acid is defined as the chemical species that produces hydrogen ions in the solution while a base is defined as the chemical species that produces hydroxide ions in the solution.
(b):
Given pH value = 10
The solution is basic in nature, thus the color of litmus will be blue.
(c):
Pure water is neutral in nature and has a pH of 7.
Thus, the solution of litmus would be purple.
How many moles are present in 5.67x1025 atoms of Carbon (C)?
Answer:
94 moles of Carbon
Explanation:
From the question,
Using Avogadro's constant
1 mole of every element contains 6.03×10²³ atoms of the element
If 1 mole of Carbon contains 6.03×10²³ atoms of Carbon,
Then, x mole of Carbon will contain 5.67×10²⁵ atoms of Carbon
1 mole of C ⇒ 6.03×10²³ atoms of C
x mole of C ⇒ 5.67×10²⁵ atoms of C
solve for x
x = (1× 5.67×10²⁵)/6.03×10²³
x = 94.03 moles of Carbon
x ≈ 94 moles of Carbon
using details and examples from the text explain how the digestive system helps your body obtain the energy it needs
Answer:
Explanation:
Select the correct answer. Which of the below is an example of mimicry that enables prey species avoid predation
What are the answers? I assume you meant to attach a photo.
Answer:
Thus, the one that is an example of mimicry that enables prey species to avoid predation is a harmless organism imitating the look of a harmful one (option B).
Explanation:
A sample of gas occupies 2.30 L at 825 mmHg and 70.0°C. What is its volume at STP
Answer:
V₂ = 2.0 Liters at STP conditions
Explanation:
Solving problem using the combined gas law
Given:
Case I Conditions Cast II Conditions
P₁ = 825mmHg P₂ = 760mm
V₁ = 2.30 Liters V₂ = ?
T₁ = 70°C + 273 = 343K T₂ = 0°C = 273K
Substitute into combined gas law assuming moles of gas remains constant; solve for unknown volume under case 2 conditions
P₁·V₁/n₁·T₁ = P₂·V₂/n₂T₂ => V₂ = P₁·V₁·T₂ / P₂·T₁ => note: in this solution, moles of gas remains constant as is disregarded in final calculation.
V₂ = (825mm)(2.3L)(273K) / (760mm)(343K) = 1.987 Liters (calculator answer) ≅ 1.9 Liters (2 sig figs based on given volume (V₁)
V₂ = 1.987 Liters ≅ 2.0 Liters (2 sig figs based on given volume (V₁)
A man pulled a food cart 4.5 m to the right for 15 seconds. What is the average speed of the food cart to the nearest tenth of a m/s?
The average speed of the food cart to the nearest tenth of a m/s is 0.3 meter per second.
How do we calculate speed?Speed of any moving body will be calculated by using the below formula as:
Speed = Distance / Time
Given that, Distance travelled to the right side = 4.5m
Time to travel = 15 sec
On putting values on the above equation, we get
Speed = 4.5 / 15 = 0.3 m/s
Hence required speed is 0.3m/sec.
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What is a sensitive device used to detect magnetic fields on the seafloor?
A. seismometer
B. geologist's compass
C. Glomar
D. magnetometer
Answer:
D. Magnetometer
Explanation:
A magnetometer is a device that measures magnetic field or magnetic dipole moment. Some magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location.
A family is driving to a nearby city. If they traveled 224.4 miles for 3.3 hours how fast were they traveling?
1.What is the maximum amount of the substance that will dissolve in 100 3
cm of water at 30°C?
A. 25 g
B. 33 g
C. 57 g
D. 125 g
2. The graph shows the solubility curve of an unknown salt. The four points on the diagram represent four solutions of the unknown salt.
Which point represents a supersaturated solution of the unknown salt? A. Q
B. R
C. S
D. T
3. The illustration below lists the pH of various substances.
Which of the following substances is the closest to a neutral pH?
A. milk
B. vinegar
C. ammonia
D. milk of magnesia
4. The figure below shows where solution X and solution Y fall on the pH scale.
Which statement correctly compares solutions X and Y?
-
A. Solution X has a higher concentration of hydroxide ions (OH ) than
solution Y.
3+
B. Solution X has a higher concentration of hydronium ions (H O ) than solution Y.
3+
C. Solution X and Y have equal numbers of hydronium (H O ) and
-
hydroxide (OH ) ions.
3+
D. Solution Y has a higher concentration of hydronium ions (H O ) than solution X.
5. The graph below shows the amount of salt that dissolves in 100
milliliters (mL) of water at various temperatures.
Based on the graph, what is the likely amount of salt that will dissolve in 200 mL of water at 90°C?
A. 35 grams
B. 40 grams
C. 80 grams
D. 100 grams
6. The graphic shows sugar in a cup before and after it has dissolved.
Which action most likely occurred in order for the sugar to dissolve?
A. The water was stirred.
B. The sugar was cooled.
C. The sugar settled to the bottom.
D. The water evaporated from the top.
7. Look closely at the illustration below showing where the compound
sodium hydroxide falls on the pH scale.
What type of compound is sodium hydroxide?
A. acid
B. base
C. element
D. salt
8.The graph shows the solubility of carbon dioxide (CO ) in water at
different temperatures.
Explain how temperature affects the solubility of carbon dioxide in water.
9.The graph shows solubility curves for four salts across different
Temperatures.
How many grams of NaCl will dissolve in 100 grams of water at 100°C?
A. 10 g
B. 33 g
C. 40 g
D. 42 g
10. The graphic shows an investigation being performed by four students.
Each student will pour 10 grams of sugar into 100 milliliters of water into
his or her container. They will stir the water gently for 20 seconds. Which
student's sugar will most likely dissolve the fastest?
A. Jennie
B. Al
C. Adriane
D. Marcus
11.Which of the following is NOT a way to increase the solubility of a solid
in water?
A. crushing the solid
B. shaking the mixture of solid and water
C. raising the temperature of the water
D. letting the mixture stand still a long time
12.The dissolved substance in a solution is the
A. solute.
B. solvent.
C. tincture.
D. suspension.
13.Which of the following refers to the concentration of a substance?
A. the size of the particles that make up a substance
B. the grams of solute dissolved per 100 g of solvent
C. the minimum volume of solvent dissolved per liter of solution at a
given pressure
D. the maximum amount of a solute that can be dissolved in a solvent
at a given temperature
14.A soil sample with a pH of 4.5 is
A. neutral.
B. acidic.
C. basic.
D. inconclusive.
15.Which of the following combinations would create the fastest chemical
reactions?
A. a whole antacid tablet and vinegar at 25 degrees Celsius
B. a whole antacid tablet and vinegar at 50 degrees Celsius
C. a crushed antacid tablet and vinegar at 25 degrees Celsius
D. a crushed antacid tablet and vinegar at 50 degrees Celsius
16.What substances change color when added to acids or bases?
A. indicators
B. electrolytes
C. insulators
D. capacitors
17.The table below shows four solutions that were prepared by dissolving
salt in water.
Which of the solutions has the highest salt concentration?
A. Solution A
B. Solution B
C. Solution C
D. Solution D
Answer:
FOr question 5, the answer is 80 gramas.
Explanation: According to the graph, when the salt is being dissolved in 100 ml of water at 90 degrees 40 grams had been dissolved. If you double the amount of water, the amount of solubility will also increase.
(Will come back later for edits)
According to the graph, when the salt is being dissolved in 100 ml of water at 90 degrees 40 grams had been dissolved. If you double the amount of water, the amount of solubility will also increase.
What does the graph shows?The graph shows the solubility curve of an unknown salt. The four points on the diagram represent four solutions of the unknown salt.The ratio of a constituent's abundance to the total volume of a mixture is called concentration. Mass concentration, molar concentration, number concentration, and volume concentration are four different categories of mathematical description.
Salt in freshwater is less than that in salt water, and the concentration of salt in the Dead Sea is greater than the concentration of salt in the oceans. The Dead Sea has a salinity of 33.7 percent, and the second-saltiest lake in the world is the Dead Sea.
Therefore, According to the graph, when the salt is being dissolved in 100 ml of water at 90 degrees 40 grams had been dissolved. If you double the amount of water, the amount of solubility will also increase.
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4. What was the original volume of a gas that expanded to 25
temperature change from 1 to 10 degrees Celsius?