Answer:
Growing population
The worlds developing regions will see 1.2 billion people added, a 20.7% increase; while the population of developed countries will increase a mere 3.3% adding 41 million to the current 1.3 billion people.
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
what type of matter is gold, an element used in making jewlery?
Answer:
Pure gold belongs to ELEMENT because it purely consists of one single element, which is Aurum (Au.)
Explanation:
When pure gold is mixed with other elements to make jewelry, it becomes a mixture.
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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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:
determine the degree of ionization at pH 2.0
Answer:
answer in the picture above
two or more substances combine to form a single new substance
Answer:
Combination reactions
Explanation:
Hope this helps:)
Which elements most easily give up electrons?
A.Oxygen, hydrogen, lithium
B.Copper, gold, silver
C.Copper, oxygen, silver
D.Silver, iodine, helium
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]
Why do we have to decide what to do in a day?
Answer:
otherwise you will be bord and have nothing to do
Explanation:
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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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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Am nevoie rapid de aceste exercitii
Answer:
I will find the answer for you
Explanation:
Just a minute
(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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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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When two or more magnetic fields overlap, the result is always a _____.
A combined magnetic field
B force of repulsion
C change in the location of the poles
D force of attraction
Answer:
A. Combined magnetic field
Answer:
A.combined magnetic field
Explanation:
CARRY ON LEARNING#
how many grams of Na2co3 will be produced from the thermal decomposition of 250.0 g of nahco3?. 157.7 g
how would changing the proportions in an alloy change its properties
Answer:
An alloy is a mixture of two or more metals which is produced with a specific proportion between metals. So, if the proportion is changed the physical characteristic would be changed as well. For example, brass musical instruments are made of brass which is a mixture (an alloy) of zinc and copper in a specific proportion. If you change a proportion, you will change the physical characteristic of brass musical instruments, and a sound they produce will be different.
Explanation:
What does the sum of oxidation numbers need to equal for a charged compound?
Answer:
The charge on the compound
Explanation:
The charge on the compound signifies that the compound is not in its neutral state.
Therefore, the oxidation state would be equal to the charge on the compound.
Answer:
The charge on the compound
Explanation:
The charge on the compound signifies that the compound is not in its neutral state.
Therefore, the oxidation state would be equal to the charge on the compound.
The volume of a gas is 3.0 L, the pressure is 1.0 atm, and the temperature is 300 K. A chemist changes one factor while keeping another constant so that the new volume is 2.0 L. Which of the following could be the new conditions?
Group of answer choices
The final pressure is 0.5 atm, while temperature is kept constant.
The final temperature is 200 K, while pressure remains constant.
The final pressure is 0.2 atm, while temperature is kept constant.
The final temperature is 350 K, while pressure remains constant.
Given the data from the question, the final temperature is 200 K, while pressure remains constant.
Basic conceptsTo obtain the correct answer to the question, we shall consider two conditions:
Case 1 (temperature is constant) Case 2 (pressure is constant) Case 1 (Temperature is constant)We shall determine the new pressure by using the combined gas equation (P₁V₁ / T₁ = P₂V₂ / T₂) as illustrated below:
Initial volume (V₁) = 3 LInitial pressure (P₁) = 1 atmTemperature = constant New Volume (V₂) = 2 L New pressure (P₂) =?P₁V₁ / T₁ = P₂V₂ / T₂
Since temperature is constant, we have:
P₁V₁ = P₂V₂
3 × 1 = P₂ × 2
3 = P₂ × 2
Divide both side by 2
P₂ = 3 / 2
P₂ = 1.5 atm
Case 2 ( pressure is constant)We shall determine the new temperature by using the combined gas equation (P₁V₁ / T₁ = P₂V₂ / T₂) as illustrated below:
Initial volume (V₁) = 3 LInitial pressure (T₁) = 300 KPressure = constant New Volume (V₂) = 2 L New pressure (T₂) =?P₁V₁ / T₁ = P₂V₂ / T₂
Since pressure is constant, we have:
V₁ / T₁ = V₂ / T₂
3 / 300 = 2 / T₂
1 / 100 = 2 / T₂
Cross multiply
T₂ = 100 × 2
T₂ = 200 K
SUMMARY
when the temperature is constant, the new pressure is 1.5 atmWhen the pressure is constant, the new temperature is 200 KFrom the calculations made above, we can conclude that the correct answer is:
The final temperature is 200 K, while pressure remains constant.
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Answer:
b
Explanation:
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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Name the Covalent compound NH3O2
The name of the covalent compound NH3 O2 is dihydroxylamine.
Naming compoundsAccording to the task content;
It follows that the given covalent compound whose name is to be written is; NH3O2.On this note, the compound possesses 2 oxygen atoms, 3 Hydrogen atoms and 1 Nitrogen atom. Hence, the name of the covalent compound is Dihydroxylamine.
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Go why?yes but why but no sense so help but yes by hypothesis
Answer:
follow hypothesis bud
Explanation:
yep
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]
Argon gas has a temperature of 180°C at a pressure of 900 torr. If the gas is heated to 370°C, what is the new pressure of Argon gas in atmospheres (atm)? (Hint: 1 atm = 760 torr)
Based on the calculations, the final pressure of this gas sample at 370°C is equal to 2.66 atm..
Given the following data:
Initial temperature = 180°C.
Final temperature = 370°C.
Initial pressure = 900 torr.
Conversion:
760 torr = 1 atm.
900 torr = 1.29 atm.
How to determine the final pressure.In order to calculate the final pressure of an ideal gas at constant volume, we would apply Gay Lussac's law.
Mathematically, Gay Lussac's law is given by this formula;
[tex]P\;\alpha \;T\\\\P=kT[/tex]
Where:
P is the pressure.T is the temperature.k is the constant of proportionality.Substituting the given parameters into the formula, we have;
[tex]\frac{P_1}{T_1} =\frac{P_2}{T_2} \\\\\frac{1.29}{180} =\frac{P_2}{370} \\\\0.0072 =\frac{P_2}{370}\\\\P_2 = 0.0072 \times 370[/tex]
Final pressure = 2.66 atm.
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An atom with more electrons than protons has an overall positive charge and is called a
positive ion
That is correct! It is a positive ion!
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 4.65 LL of CO2CO2 gas at 22 ∘C∘C at 793 mmHg mmHg is used, what is the final volume, in liters, of the gas at 35 ∘C∘C and a pressure of 743 mmHg mmHg , if the amount of CO2CO2 does not change?
Answer:
About 7.9 L.
Explanation:
We can utilize the ideal gas law. Recall that:
[tex]\displaystyle PV = nRT[/tex]
Because the amount of carbon dioxide does not change, we can rearrange to formula to:
[tex]\displaystyle \frac{PV}{T}= nR[/tex]
Because the right-hand side stays constant, we have that:
[tex]\displaystyle \frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2} = nR[/tex]
Hence substitute initial values and known final values:
[tex]\displaystyle \begin{aligned} \frac{(793\text{ mm Hg})(4.65 \text{ L})}{(22 \text{ $^\circ$C})} & = \frac{(743 \text{ mm Hg})V_2}{(35\text{ $^\circ$C})} \\ \\ V_2 & = 7.9\text{ L}\end{aligned}[/tex]
Therefore, the final volume is about 7.9 L.
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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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
Starting with the following equation,
BaCl2(aq) + Na3PO4(aq) → Ba3(PO4)2(S) + NaCl(aq)
Calculate the mass in grams of BaCl2 that will be required to produce 50.5 grams of Ba3(PO4)2.
In the double displacement reaction between BaCl₂ and Na₃PO₄, 52.4 g of BaCl₂ are required to produce 50.5 g of Ba₃(PO₄)₂.
What is stoichiometry?Stoichiometry refers to the relationship between the quantities of reactants and products before, during, and following chemical reactions.
Step 1: Write the unbalanced equation.BaCl₂(aq) + Na₃PO₄(aq) → Ba₃(PO₄)₂(s) + NaCl(aq)
Step 2: Balance the equation.We will use the trial and error method. We will:
Multiply BaCl₂ by 3 to balance Ba atoms.Multiply Na₃PO₄ by 2 to balance P atoms.Multiply NaCl by 6 to get the balanced equation.3 BaCl₂(aq) + 2 Na₃PO₄(aq) → Ba₃(PO₄)₂(s) + 6 NaCl(aq)
Step 3: Calculate the mass of BaCl₂ required to produce 50.5 g of Ba₃(PO₄)₂.The mass ratio of BaCl₂ to Ba₃(PO₄)₂ is 624.69:601.93.
50.5 g Ba₃(PO₄)₂ × 624.69 g BaCl₂/601.93 g Ba₃(PO₄)₂ = 52.4 g BaCl₂
In the double displacement reaction between BaCl₂ and Na₃PO₄, 52.4 g of BaCl₂ are required to produce 50.5 g of Ba₃(PO₄)₂.
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