Answer:1950-200
Explanation:
During 1950-2000 of the following 50-year intervals has the world's population increased the most. Hence, option D is correct.
What is population?The whole number of people or inhabitants in a country or region.
The world's population increased from 2.5 billion in 1950 to around 7.3 billion in 2015 and is expected to continue to rise until 2050/2100 under most UN.
During 1950-2000 of the following 50-year intervals has the world's population increased the most. Hence, option D is correct.
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smoking cigarettes is banned in petrol stations because of the risk of explosions.
Explain why Flames can cause explosions in petrol stations even if they never come into direct contact with any liquid petrol.
help pls!
Answer:
well it is because of mainly what we call reaction the petrol are highly reactive with the flames
Using the periodic table, which of the elements below would be a poor conductor of electricity, be a gas, and may have a color?
a. Zinc
b. Cobalt
c. Chlorine
d. Calcium
Name the two geometrical isomer of hydrocarbon
Answer:
alkenes and cyclic compounds
Sugar (C12H22011) is a molecular substance. Which of the following properties would you expect it to
have?
a. conducts electricity in water
b. doesn't dissolve in water
c. held together by opposite charges
d. low melting point
what is the formula to find the volume of a marble
Individual marble:
4/3_?_ R^3Answer:
Individual Marble
Use the formula 4/3_?_ R^3, to solve for the volume. Here, R is the radius, or half of D. ^3 means the radius is cubed.
Explanation:
Which word equation shows lithium oxide being formed from the reaction between oxygen and lithium? oxygen lithium oxide right arrow. lithium lithium oxygen right arrow. lithium oxide oxygen lithium right arrow. lithium oxide lithium oxide right arrow. lithium oxygen
Answer:
lithium lithium (or 2lithium) + oxygen ->
Explanation:
Your welcome
A substance was analyzed and found to have a pH of 3 and turn blue litmus paper to red. The substance is most likely
Three elements, A, Q, and Z, have the molar masses indicated in the table below. Given a compound with a composition of 15.66% A and 84.34% Z by mass, what is the empirical formula of this compound?
element symbol molar mass
A 15.45 g/mol
Q 20.05 g/mol
Z 41.62 g/mol
Answer:
AZ₂
Explanation:
The formed compound will not contain Q because mass percentages, %A and %B, form 100% of the compound.
Steps
Change % of each element into grams.Convert grams of each element into moles by dividing grams by molar mass.Divide all moles by the smallest number of moles.If the moles are all whole numbers, then you’re done and that’s your empirical formula.If not, multiply all moles by number such that everything is a whole number.Solving
We have 15.66g of A and 84.34g of ZMoles of A, n(A) = 15.66/15.45 = 1.01 molesMoles of Z, n(Z) = 84.34/41.62 = 2.02 molesA = 1.01/1.01 = 1 and Z = 2.02/1.01 = 2Therefore, the empirical formula is AZ₂Name the following carboxylic acid
COOH
A. 3-ethyl-2-methylheptanoic acid
B. 2-ethyl-1-methylhexanoic acid
C. 2-methyl-3-ethylheptanoic Acid
The name of the carboxylic acid would be 2-methyl-3-ethylheptanoic acid.
Naming or carboxylic acids
Carboxylic acids are named based on the longest carbon chain and the counting starts from the carboxylic acid's functional group.
Thus, in this case, the compound would be a heptanoic acid because the longest chain towards the functional group has 7 carbons.
This means 2 branches exist in the compound. The first one has a single carbon while the second one has 2 carbon atoms. This means they are methyl and ethyl groups respectively.
The branches are located on the second and third carbon on the main chain. Thus the compound's name is 2-methyl-3-ethylheptanoic Acid.
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Complete the chart on the characteristics of bonds
Answer:
Face value. Corporate bonds normally have a par value of $1,000, but this amount can be much greater for government bonds.
Interest. ...
Coupon or interest rate. ...
Maturity. ...
Issuers. ...
Rating agencies. ...
Tools and tips.
Explain the relashionship between carbon dioxide, the human population and use of fossil fuels.
Answer:
More people means more demand for oil, gas, coal and other fuels mined or drilled from below the Earth's surface that, when burned, spew enough carbon dioxide (CO2) into the atmosphere to trap warm air inside like a greenhouse
Explanation:
hope this helps
pls mark brainliest
where would you find water on the ph scale?
Answer: between 6.5 and 8.5
Explanation:
As shown in my science book it appears in the ph scale
What is the boiling point of liquid c when the
Answer:
100 degree is the answer of given statement
Calculate the mass (in grams) of 3.85 x 1024 carbon atoms.
Round your answer to two decimal places.
Answer:
You can get to the answer in two steps:
calculate: 3.40⋅1022 atoms = x mol ?
using Avogadro's constant.
calculate: x mol = ? grams,
using the atomic mass of Helium.
Step 1
Avogadro's constant says that 1 mole of any atom contains 6.022⋅1023 atoms. In this case you have 3.40⋅1022 atoms:
3.40⋅1022atoms6.022⋅1023atomsmol = 5.65⋅10−2mol
Step 2
The atomic mass of helium (He) will give you the weight of one mole of this molecule: 1 mol = 4.00 gram:
4.00gmol⋅5.65⋅10−2mol = 0.226g
So the 3.40⋅1022 helium atoms weigh 0.226 gram.
A sample of P2Cl5 contains 179 g of phosphorous, how many grams of chlorine are present? Please show step by step thx!
Answer:
About 512 g.
Explanation:
We are given a sample of P₂Cl₅ that contains 179 grams of phosphorus, and we want to determine the grams of chlroine that is present.
Thus, we can convert from grams of phosphorus to moles of phosphorus, moles of phosphorus to moles of chlorine, and moles of chlorine to grams of chlorine.
From the formula, there are two moles of P for every five moles of Cl. The molecular weights of P and Cl are 30.97 g/mol and 35.45 g/mol, respectively. Hence:
[tex]\displaystyle 179\text{ g P} \cdot \frac{1\text{ mol P}}{30.97\text{ g P}} \cdot \frac{5\text{ mol Cl}}{2\text{ mol P}} \cdot \frac{35.45\text{ g Cl}}{1\text{ mol Cl}} = 512\text{ g Cl}[/tex]
In conclusion, there is about 512 grams of chlorine present in the sample.
Alternatively, we can mass percentages. The mass percent of phosphorus in P₂Cl₅ is:
[tex]\displaystyle \% \text{P} = \frac{2(30.97)}{5(35.45) + 2(30.97)} = 25.90\%[/tex]
Because there are 179 grams of phosphorus, the total amount of sample present is:
[tex]\displaystyle \begin{aligned} 25.90\% \cdot m_T & = 179\text{ g P} \\ \\ m_T & = 691.1 \text{ g}\end{aligned}[/tex]
Therefore, the amount of chlorine present is 691.1 g - 179 g, or about 512 g, in agreement with our above answer.
What is the relationship between the enthalpy (AH) and entropy (AS) of a
reaction that is spontaneous at higher temperatures but not at lower
temperatures?
The relationship between the enthalpy (ΔH) and entropy (ΔS) of a
reaction that is spontaneous at higher temperatures but not at lower
temperatures is +ΔH, - Δs.
Relationship between enthalpy and entropy
The relationship between enthalpy (ΔH) and entropy (ΔS) is given by Gibs free energy.
ΔG = ΔH - TΔs
When ΔH < 0 and Δs < 0, ΔG = -ve (-ΔH, - Δs) (for lower temperature)
Also, when ΔH < 0 and Δs = +, ΔG = -ve (-ΔH, +Δs) (for all temperature)
When ΔH > 0 and Δs < 0, ΔG = -ve (+ΔH, - Δs) (for higher temperature)
Thus, the relationship between the enthalpy (ΔH) and entropy (ΔS) of a
reaction that is spontaneous at higher temperatures but not at lower
temperatures is +ΔH, - Δs.
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4Na(s)=+O2(g)->2NA2)(s)
How many grams of Na2O is produced when 57.5g an Na reacts
When a solution is saturated, and additional solid solute is added, what happens?
Answer:
super saturation takes place.
3. How many grams are there in 5.5 mole of Sulfur [S=32].
Answer:
176g
Explanation:
Given :
moles = 5.5
molar mass (sulfur ) = 32u
given mass = ?
Solution:
mole = given mass/molar mass
5.5 = given mass/ 32
5.5×32=given mass
176 g = given mass
The following data was collected when a reaction was performed experimentally in the laboratory. Reaction Data Reactants Products Fe2O3 Al Al2O3 Fe Starting Amount in Reaction 3 moles 5 moles ? ? Determine the maximum amount of Fe that was produced during the experiment. Explain how you determined this amount.
The maximum amount, in grams, of Fe that would be produced during the experiment, will be 280 grams
Sotichiometric calculationFrom the equation of the reaction:
[tex]Fe_2O_3 + 2Al -- > 2Fe + Al_2O_3[/tex]
The mole ratio of [tex]Fe_2O_3[/tex] to Al is 1:2.
But 3 moles and 5 moles of reactants respectively started the reaction. Thus, Al is limited in availability and will determine the amount of products that will be produced.
The mole ratio of Al and Fe is 1:1, therefore, a maximum of 5 moles of Fe will be produced from the reaction.
5 moles Fe = 5 x 56 = 280 grams
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The electron configuration of an element is shown below.
1s^22s^22p^5
Name the group this element belongs to in the periodic table and explain your answer. Based on the electron configuration, explain how many electrons it is likely to receive from the atom of another element during the formation of a bond.
Answer:
Fluorine 1s2 2s2 2p5
Explanation:
it is likely to receive 1 electron
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In the periodic table, this element belongs to the 17th group. As a result, the element has a tendency to gain one electron during bond formation in order to achieve octet.
What is octet state?According to the octet rule, atoms are most stable when their valence shells contain eight electrons. The eight electrons that fill an atom's outermost shell are known as octets.The octet rule is significant because it predicts how atoms will bond based on their valence electrons' outer shells. Atoms form a certain number of bonds in order to share electrons with other atoms, resulting in an octet of eight electrons. For example, the outer shell of oxygen contains only six electrons.electronic configuration is:
[tex]1s^22s^22p^5[/tex]
The given element contains two electrons in the 2s orbital and five electrons in the 2p orbital. As a result, the energy level with n = 2 is the outermost energy level in this case. As a result, the element has 2 + 5, or 7 valence electrons. Elements with 7 valence electrons are classified as belonging to periodic table group 17.The element has 7 valence electrons, so it requires one more electron to achieve the stable octet state. As a result, the element has a tendency to gain one electron during bond formation in order to achieve octet.To learn more about octet rule, refer:
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How many liters of 4.000 M sodium bromide solution are needed to
make 0.250 L of 0.200 M sodium bromide?
Calculate the molarity of 0.060 moles NaHCO3 in 1500. mL of solution
Answer:
= 0.4 M
Explanation:
data:
moles = 0.060 moles
volume = 1500 ml
= 1500 / 1000
= 1.5 dm^3
solution;
molarity = [tex]\frac{no. of moles}{volume in dm^3}[/tex]
= 0.060 / 1.5
molarity = 0.4 M
Lab: Plate Boundaries and Movement Lab Report.
A Plate Boundaries and Movement Lab Report is a report that shows the records of all the data relating to the movement of Plate Boundaries and their movements.
What are Plates in this context?A tectonic plate is also described or referred to as a Lithosperic Plate. In Geography, it is described as a slab of rock that is not shaped regularly.
In most cases, it comprises continental and oceanic lithosphere.
Why is it crucial to record the movement of plates and their boundaries?Plate Boundaries and their movement are largely linked to volcanic activities and earthquakes. This means that they can be used to predict when any of the above-mentioned events may happen.
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Ionic bonds form between which two types of elements?
Answer:
Cation and anion.
Cation is a positive ion.
Anion is negative ion.
E.g.: NaCl, CaF2, KBr
A balloon contains 7.2 L of
He. The pressure is reduced
to 2.00 atm and the balloon
expands to occupy a volume
of 25.1 L. What was the initial
pressure exerted on the
balloon?
Given:
Unknown:
Formula:
Solution:
Final Answer:
Apply Boyles law
P1V1=P2V27.2(2)=25.1P214.4=25.1P_2P_2=0.57atmRemember
If Volume is four times increased pressure is 4 times decreased
What is the pH of a 4.2 x 10^-3 solution of HCl?
Answer:
pH = 2.38
Explanation:
Recall that HCl is a strong acid and hence dissociates completely into H⁺ and Cl⁻ ions. Thus, the solution's H⁺ concentration is equivalent to the acid concentration. That is, [H⁺] = 4.2 × 10⁻³ M.
Therefore, the pH of the solution is:
[tex]\displaystyle \begin{aligned}\text{pH} & = -\log[\text{H}^+] \\ \\ & = -\log (4.2\times 10^{-3}) \\ \\ & = 2.38\end{aligned}[/tex]
Answer:
HCl + H[tex]\\ 2[/tex]O —> Cl- + H[tex]\\ 3[/tex]O+
pH = -log [H[tex]\\ 3[/tex]O+] = -log [4.2 x 10^-3] = 2.38
—
We assume that hydrochloric acid will undergo complete dissociation in water to give stoichiometric H3O+ ion, according to the given reaction.
—
Have a nice day!!
A 3.24-gram sample of NaHCO3 was completely decomposed in an experiment.
2NaHCO3 → Na2CO3 + H2CO3
In this experiment, carbon dioxide and water vapors combine to form H2CO3. After decomposition, the Na2CO3 had a mass of 2.19 grams.
Determine the mass of the H2CO3 produced.
Calculate the percentage yield of H2CO3 for the reaction. Show your work or describe the calculation process in detail.
PLEASE HELP, WILL MARK BRAINLIEST!!!
Mass of H2CO3 = 1.05g
Givens: NaHCO3 = 3.24
Na2CO3 = 2.19
Mass of H2CO3 = mass of NaHCO3 - mass of Na2CO3
Mass of H2CO3 = 3.24g - 2.19g
Mass of H2CO3 = 1.05g
How do you find the mass number?The number of protons and the number of neutrons combine to determine the mass number of an element. Mass number = proton + neutron. If you want to calculate the number of neutrons an atom has, you can simply subtract the number of protons or atomic numbers from the mass number.
Divide the mass of a substance in grams by the molecular weight. This will give you the number of moles of the substance in a particular mass. For 12 g of water, (25 g) / (18.015 g / mol) = 0.666 mol.
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Which of the following indicates an endothermic reaction? I will mark as brainliest if correct.
Answer:
A + B → C + D + heat
Explanation:
A. A+B+heat⇒C+D
In an endothermic reaction, the system requires energy/heat, the enthalpy change is positive.
This is an impossible formula. If it were real, determine the molar mass of:
Cr4(PO4)3
Answer:
Molar Mass (Cr₄(PO₄)₃): 492.894 g/mol
Explanation:
First, collect the individual molar masses of each element. These values are found on the periodic table under each respective element.
Chromium (Cr): 51.996 g/mol
Phosphorus (P): 30.974 g/mol
Oxygen (O): 15.999 g/mol
The quantity of each element is determined by the subscript next to it. If their is a subscript directly to the right of a set of parentheses, multiply each element within the parentheses by the subscript.
Chromium (Cr): 4
Phosphorus (P): 1 x 3 = 3
Oxygen (O): 4 x 3 = 12
Finally, the total molar mass of the compound is the collective molar masses of each element times the quantity of each element.
Molar Mass (Cr₄(PO₄)₃): 4(51.996 g/mol) + 3(30.974 g/mol) + 12(15.999 g/mol)
Molar Mass (Cr₄(PO₄)₃): 492.894 g/mol