Answer:
28ft
Explanation:
if it's a square then each side is equal
the square root of 49 is 7
each side is 7 ft
7 ft times 4 sides is 28ft
How many people were considered undernourished in Latin America and the Caribbean in 2018?
Question 4 options:
513.9 million
2.6 million
821.6 million
42.5 million
A 20 g gold coin is heated from 10°C to 50°C ( CAu is 0.13 J/g−°C ). What is the △H ? (Hint: Remember ΔH=q, so if you solve for q, you might have your answer!)
Now
[tex]\\ \rm\rightarrowtail Q=mc\delta T[/tex]
[tex]\\ \rm\rightarrowtail Q=20(40)(0.13)[/tex]
[tex]\\ \rm\rightarrowtail Q=800(0.13)[/tex]
[tex]\\ \rm\rightarrowtail Q=104J[/tex]
.
Which is not a property of magnets?
AThey point north when allowed to swing freely on a string.
B They attract or repel other magnets.
C Their force of attraction is strongest in the middle of the magnet.
D They attract iron and other materials containing iron.
Explanation:
Their force of attraction is strongest in the middle of the magnet.
Find the empirical formula of a compound that contains 34.97 g of Fe and 15.03 g of O.
The Arctic’s tundra, though very cold for much of the year, is said to be more strongly defined by its cool summer temperatures, instead of its winter lows. Why?
Because these low summer temperatures can cause a rain-shadow effect
Because these low summer temperatures limit the growth of plants in the summer
Because these low summer temperatures can rapidly changing weather
Because these low summer temperatures chase large land masses of ice that do not even totally melt in the summer.
Answer: Because these low summer temperatures limit the growth of plants in the summer
Explanation: Took the test!
In an ecosystem, like Arctic's tundra, though very cold for much of year, is said to be more strongly defined by its cool summer temperatures, instead of its winter lows because these low summer temperatures limit growth of plants in summer.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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Which of the following is a nonmetal?
A.
potassium (K)
B.
aluminum (Al)
C.
calcium (Ca)
D.
chlorine (Cl)
Which elements most easily give up electrons?
A.Oxygen, hydrogen, lithium
B.Copper, gold, silver
C.Copper, oxygen, silver
D.Silver, iodine, helium
Determine the molar solubility of BaF2 in a solution containing 0.0550 M LIF. Ksp (BaF2) = 2.45 x 10^-5
Answer:
8.1*10^-3 or 0.00809917
Explanation:
Step 1: Identify the common ion
LiF and BaF2 both share the ion F^- therefore we can interchange the molarity of LiF for F.
Step 2: Set up a balanced equation
BaF2---Ba2+ + 2F
Step 3: Set up a solubility ice table
initial- Ba^2+: 0 2F: 0.0550
change- S 2F: S^2(exponent is result of coefficient)
Step 4: Set up Ksp equation
2.45*10^-5=[S][S]^2
Step 5: Plug in values
2.45*10^-5=[S][0.0550]^2
S=8.1*10^-3
(a)Determine the number of KNO3 molecules in 0.750 mol KNO3.
(b) What is the mass (in milligrams) of 2.39 x 1020 molecules of Ag2SO4.
(c) Estimate the number of NaHCO2 molecules in 3.429 g of NaHCO2.
A. The number of molecules in 0.750 mole of KNO₃ is 4.515×10²³ molecules
B. The mass (in milligrams) of 2.39×10²⁰ molecules of Ag₂SO₄ is 124 mg
C. The number of molecules in 3.429 g of NaHCO₂ is 3.04×10²² molecules
Avogadro's hypothesis
1 mole of substance = 6.02×10²³ molecules
A. How to determine the number of molecules1 mole of KNO₃ = 6.02×10²³ molecules
Therefore,
0.750 mole of KNO₃ = 0.75 × 6.02×10²³
0.750 mole of KNO₃ = 4.515×10²³ molecules
B. How to determine the mass of Ag₂SO₄6.02×10²³ molecules = 312 g of Ag₂SO₄
Therefore,
2.39×10²⁰ molecules = (2.39×10²⁰ × 312) / 6.02×10²³
2.39×10²⁰ molecules = 0.124 g
Multiply by 1000 to express in mg
2.39×10²⁰ molecules = 0.124 g × 1000
2.39×10²⁰ molecules = 124 mg of Ag₂SO₄
C. How to determine the number of molecules68 g of NaHCO₂ = 6.02×10²³ molecules
Therefore,
3.429 g of NaHCO₂ = (3.429 × 6.02×10²³) / 68
3.429 g of NaHCO₂ = 3.04×10²² molecules
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Am nevoie rapid de aceste exercitii
Answer:
I will find the answer for you
Explanation:
Just a minute
220 mL of oxygen gas was collected over water. The total pressure of oxygen plus water vapor was 745.8 mmHg at 25.0°C. What is the pressure, in mmHg, exerted by only the oxygen gas?
Since 220 mL of oxygen gas was collected over water, the pressure exerted by only the oxygen gas is 720.8 mmHg
Pressure of gas collected over waterThe total pressure of a gas collected over water is given by P = P' + p where
P = pressure of oxygen gas and p = vapour pressure of water at 25 °C = 25 mmHgMaking P' subject of the formula, we have
P' = P - p
Since the total pressure of oxygen plus water vapor is P = 745.8 mmHg, substituting the values of the variables into the equation, we have
P' = P - p
P' = 745.8 mmHg - 25 mmHg
P' = 720.8 mmHg
So, Since 220 mL of oxygen gas was collected over water, the pressure exerted by only the oxygen gas is 720.8 mmHg
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If the pH is 6.1,what is the concentration of H^+?
Hi!
[tex]\\ \sf\rightarrow pH=-log[H^+][/tex]
[tex]\\ \sf\rightarrow -log[H^+]=6.1[/tex]
[tex]\\ \sf\rightarrow log[H^+]=-6.1[/tex]
[tex]\\ \sf\rightarrow [H^+]=10^{-6.1}[/tex]
[tex]\\ \sf\rightarrow [H^+]=7.94M[/tex]
Metals can be distinguished by dissolving them in fuel and them burning that fuel. For example, calcium will turn orange and copper will turn green. Is this because of blackbody radiation or atomic transitions that you see in line spectra?
Copper will turn green and calcium will turn orange. this is as a result of the atomic transitions visible in line spectra
What components make up transitions?Transition elements are substances with partially filled d orbitals, sometimes referred to as transition metals. According to IUPAC, a transition element is an element with a partially filled d subshell or one with the capacity to create stable cations that has an unfilled d orbital.
Why are transitional elements called that?As a result of their transitional behavior between s-block or p-block elements, the d-block elements are referred to as transition elements. Their characteristics are intermediate between those of the covalently-bonded, highly reactive s-block metallic elements and those of the p-block elements.
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buffer is prepared by adding 275 mL of .676M of HCl to 500 mL of .525M sodium acetate. What is the pH?
The pH of the buffer prepared by adding 275 mL of .676M of HCl to 500 mL of .525M sodium acetate is 6.45.
How to calculate pH?The pH of a buffer solution can be calculated by initially calculating the millimoles of both the conjugate base and acid.
Millimoles of hydrochloric acid = 275mL × 0.676M = 185.9millimolesMillimoles of sodium acetate = 500mL × 0.525M = 262.5millimolesFrom, Henderson Hasselbalch equation,
pH = pKa + log conjugate base/acid
pka of HCl = -6.3
-6.3 + log 262.5/185.9
6.3 + 0.15
pH = 6.45
Therefore, the pH of the buffer prepared by adding 275 mL of .676M of HCl to 500 mL of .525M sodium acetate is 6.45.
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Select the correct answer.
Iron oxide reacts with aluminum to give aluminum oxide and iron. What kind of chemical reaction is this?
Answer:
Single-replacement reaction
Explanation:
Single-replacement reactions, aka. single-displacement reactions, involve one element/ion in a compound being replaced by another element/ion. In this case, aluminum is replacing the iron in the compound.
If you need help visualizing, the equation looks like this:
Fe₂O₃ + Al³⁺ --> Al₂O₃ + Fe³⁺
please help!!!
Sulfur (S) has 16 protons and 16 neutrons. How many electron shells does an element of sulfur have?
3
4
2
1
Answer:
Sulfur (S) has 3 shells.
Explanation:
The first shell can have up to 2 electrons. The second and third shells have up to 8 electrons as well. This makes the maximum of each shell to be 2, 10, and 18. Sulfur has 16 electrons so it has more than the second shell but less than the third shell. So, it will have 3 shells with a valence of 2 since it is missing 2 electrons to create a full shell.
Determine whether or not the mixing of each of the two solutions indicated below will result in a buffer.
Drag the appropriate items to their respective bins.
Sinve CH3NH2 is weak base and its salt is CH3NH3Cl, mixing 125.0 mL of CH3NH2 and 120.0 mL of CH3NH3Cl so produce a buffer.
What is a buffer?A buffer is a solution which resists changes to its pH when a small quantity of strong acid or base is added to it..
A buffer is made from a weak acid and its salt or a weak base and its salt.
From the given options, CH3NH2 is weak base and its salt is CH3NH3Cl.
Therefore, mixing 125.0 mL of CH3NH2 and 120.0 mL of CH3NH3Cl so produce a buffer.
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A person is going for a walk in the evening. To make sure that she can be seen walking when it gets dark, she wears a glow stick around her neck. The glow stick can be used as a light source when she bends the stick. Although the stick is sealed, bending the stick allows two chemicals to come in contact and react with each other. During the chemical reaction, light is given off by the glow stick.
When the reaction stops, light is no longer given off. What happens to the mass of the glow stick after the chemical reaction occurs? Explain citing evidence from the prompt and identify the scientific law that supports your explanation.
(give me claim,evidence,reasoning)
From the law of conservation of mass, the mass of the glow stick does not change after the reaction.
Law of conservation of massFrom the law of conservation of mass we know that mass can neither be created nor destroyed but is converted from one form to another. Since the mass of the system must remain unchanged, It then follows that the mass of the glow stick must remian the same.
Therefore, the mass of the glow stick does not change after the reaction following the law of conservation of mass.
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Remove all the tape pieces from part A, and throw them in the trash. Next, follow these steps to compare pieces of sticky tape that have different charges:
Tear off two pieces of tape that are about 15 cm (6 inches) long. Similar to part A, fold under a half inch of each piece to make the strips easier to pull off.
Stick one of the pieces onto the tabletop. Smooth the tape down.
Stick the second piece of tape onto the tape piece you just placed. Do not cover the tab of the first piece of tape.
Grasp one tape tab in each hand. Carefully pull both pieces off the table and separate them. Turn the non-sticky sides of the tape toward each other.
What do you observe? If there’s an interaction, explain whether the tape pieces attract or repel each other. (ANSWER ASAP)
The interaction which will occur when the non sticky tape pieces are turned towards each other is attraction.
What is Attraction?This involves the coming together of objects as a result of a force. When non-sticky sides of the tape are brought towards each other attraction takes place due to the sticky content.
This however wears off after some time thereby making it the most appropriate choice.
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Why do we have to decide what to do in a day?
Answer:
otherwise you will be bord and have nothing to do
Explanation:
The boulder shown below has a weight of 10,000 N & is 500 m above the ground. How much gravitational potential energy does the boulder have?
Answer:
5,000,000 joules
Explanation:
Formula for Potential Energy =mgh
mass*gravity*height
mass=weight ÷ by gravity
10000÷10= 1000
1000×10×500m=5,000,000 joules
how many grams of lead II chloride are produced from the reaction of 15.3 g of NaCl and 60.8 gr of Pb(NO3)2?
The mass, in grams, of lead that will be produced from the illustrated reaction would be 71.47 grams
Stoichiometric reactionsFrom the balanced equation of the reaction:
Pb(NO3)2 + 2NaCl ---> PbCl2 + 2NaNo3
Mole ratio of Pb(NO3)2 and NaCl = 1:2
Mole of 15.3 g NaCl = 15.3/58.4
= 0.257 moles
Mole of 60.8 g PbCl(NO3)2 = 60.8/331.2
= 0.184 moles
Thus, NaCl is limiting.
Mole ratio of NaCl to PbCl2 = 1:1
Mas of 0.257 moles PbCl2 = 0.257 x 278.1
= 71.47 grams
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Describe how distillation process makes water soft
Answer:
Distillation can be used to separate and collect a liquid from a solution. Distillation can also be used to soften water as the water evaporates as it is heated and the ions are left behind. Hard water can be softened by adding sodium carbonate (washing soda) or by passing the water through an ion-exchange column.
Explanation:
0.75 mol hydrogen sulfide (H2S)
Answer:
• Information and media literacy
Directions
Read the instructions for this self-checked activity. Type in your response to each question, and check your answers. At the end of the activity, write
brief evaluation of your work.
Activity
Part A
Now that you have analyzed the resources provided in the lesson, write your own response to the question, What is the main reason the US Civil
War started? Base your
Explanation:
• Information and media literacy
Directions
Read the instructions for this self-checked activity. Type in your response to each question, and check your answers. At the end of the activity, write
brief evaluation of your work.
Activity
Part A
Now that you have analyzed the resources provided in the lesson, write your own response to the question, What is the main reason the US Civil
War started? Base your
Answer: =378.94000053g
Explanation:
I think that explains it
In the reaction
Al2S3(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2S(g),
how many moles of HCl are used for each mole of AlCl3 formed?
If you start with 10 carbon and 3 Hydrogen, what will you end with?
Hydrocarbons are composed of hydrogen and carbon only and the hydrocarbon produced will differ according to their mole ratio.
What are hydrocarbons?Hydrocarbons are compounds composed only of carbon and hydrogen.
Hydrocarbons are very large families of compounds which have a common property of being combustible.
Hydrocarbons include:
alkanesalkenes and alkynesThe mole ratio of the carbon to hydrogen in each type of hydrocarbon differs.
Therefore, starting with 10 carbon and 3 Hydrogen, the hydrocarbon produced will differ according to their mole ratio.
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Which type of resources cannot be replenished by natural processes in a reasonably short period of time?
A: nuclear waste
B: natural resources
C: nonrenewable resources
D: renewable resources
Kevin and Lisa get into a deep discussion. Kevin believes adding HOT WATER to a test tube that has baking soda will cause the substances to react faster. Lisa, thinks he is wrong and believes that the HOT WATER may cause the substances to not react normally. Based on what you learned from the QUIZZIZZ ACTIVITY, whose side would you take in this argument????
I agree with idea of Kevin because bakong soda dissociates faster in hot water than cold water.
How baking soda reactivity increase in hot water?Baking soda is a chemical that can undergo a decomposition reaction when heated. At 80 degrees Celsius, sodium bicarbonate starts to break down into sodium carbonate (Na2CO3), water (H2O) and carbon dioxide (CO2) which is ready for reaction with other chemical.
So we can conclude that Kevin idea is correct because bakong soda dissociates faster in hot water than cold water.
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If 3.500 moles of water react completely according to the following equation, how much heat must be absorbed in kilojoules? 6CO2+6H2O→C6H12O6+6O2ΔH=2,803 kJ
The amount of heat absorbed in kilojoules when 3.5 moles of water react is 1635.08 KJ
Balanced equation6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ ΔH = 2803 KJ
From the balanced equation for above,
6 moles of water reacted to absorb 2803 KJ of heat
How to determine the heat absorbedFrom the balanced equation for above,
6 moles of water reacted to absorb 2803 KJ of heat
Therefore,
3.5 moles of water will react to absorb = (3.5 × 2803) / 6 = 1635.08 KJ of heat
Thus, 1635.08 KJ of heat were absorbed by the reaction.
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Calculate the (H3O+) for a solution whose pH is 6.79
Note: blank 1 should have three significant figures
The answer is: Blank 1 X 10^Blank 2
Answer:
Explanation:
alculate the (H3O+) for a solution whose pH is 6.79
Note: blank 1 should have three significant figures
The answer is: Blank 1 X 10^Blank 2
The pH of a solution is the negative logarithm of H₃O⁺ ion concentration.The concentration of H₃O⁺ ions in a solution with a pH of 6.79 is 1.6 × 10⁻⁷M.
What is pH ?pH of a solution is the measure of its acidity or basicity. Mathematically it is the negative logarithm of its H₃O⁺ ion concentration. A solution with a pH of 7 is neutral.
The solution with a pH below 7 is acidic and above 7 is basic. Thus, the higher H+ ion concentration, then the pH will be lower and more acidic the solution.
It is given that the pH of the solution is 6.79. The concentration of H₃O⁺ ions in the solution is calculated is calculated as follows:
pH = -log ( H₃O⁺)
6.79 = -log( H₃O⁺
[ H₃O⁺] = antilog (-6.79)
= 1.6 × 10⁻⁷M
Hence, the hydronium ion H₃O⁺ ion concentration of the solution of pH 6.79 is 1.6 × 10⁻⁷M.
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