Answer:
Explanation:
Major periodic trends include: electronegativity, ionization energy, electron affinity, atomic radius, melting point, and metallic character. Periodic trends, arising from the arrangement of the periodic table, provide chemists with an invaluable tool to quickly predict an element's properties.
Have you heard of the campaign: “Say No To Plastics”. Coin a few more slogans of this kind. There are certain governmental and non-governmental organisations who educate the general public on how to make wise use of plastics and develop environment friendly habits. Find out organisations in your area which are carrying out awareness programmes. If there is none, form one.
Answer:
Helping Hand Organization
Determine the number of protons and electrons in each ion-
(a) Na
(b) Ba²+
(c) 0²-
(d) Co³+
Answer:
(a) protons: 11 electrons:11
(b) protons: 56 electrons: 54
(c) protons: 8 electrons: 10
(d) protons: 27 electrons: 24
Explanation:
I NEED HELP ASAP PLEASE !!
Answer:
The last option. Because it's not a curate or precise on the dot.
Consider the following element 6C, Na Mg, P, S, CL, Ni :which of these can form form hydride by electovalent bonding?, Can be used to catalye a chemical reaction? , can be used in radioactive dating?, Can form an acid anhydride?, Exhibit both metallic and non-metallic behavior?
The periodic table is an arrangement of the elements in order of increasing reactivity. The elements that are more reactive are found at the left hand side of the table among the metals. The reactive non metals are found at the right hand side of the table.
Element which of these can form form hydride by electrovalent bonding - NaElement that can be used to catalyze a chemical reaction - NiElement that can be used in radioactive dating - CElement that can form an acid anhydride - Cl, P, SElement that exhibit both metallic and non-metallic behavior - NoneLearn more about the periodic table:https://brainly.com/question/11155928
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minoxidil 5% versus combined fractional co2 laser and topical minoxidil 5% in treatment of male androgenetic alopecia.
Objective: To compare the efficacy of topical minoxidil 5% alone and combined topical minoxidil 5% and fractional laser in the treatment of male androgenic alopecia and detection of any side effects occurring with each line of treatment.
Patients and Methods: This prospective randomized comparative controlled study was conducted for one year on 40 patients with male androgenic alopecia attending our Patient. Patients were classified into two groups: Group A received minoxidil alone (minoxidil group) and group B where patients received minoxidil plus fractional CO2 laser.
Results: In groups A and B, there was a statistically significant improvement between the clinical assessment scale at baseline and after 1 month (p<0.001). Also, there was a statistically significant improvement between the clinical assessment scale after 1 month and after 3 months (p=0.002). In group A, there was a statistically significant improvement between the clinical assessment scale at baseline and after 1 month, however, there was no statistically significant improvement between the clinical assessment scale and after 3 months. In group B, there was a statistically significant improvement between the clinical assessment scale at baseline and after 1 month, however, also, there was a statistically significant improvement between the clinical assessment scale and after 3 months.
Conclusion: Our study revealed the superiority of combination therapy, using a fractional laser and 5% minoxidil, over 5% minoxidil alone, for the treatment of male AGA, with no serious adverse effects of treatment identified.
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While burning coal and charcoal, you notice that coal releases more heat than charcoal. What does that mean?.
While burning coal and charcoal, you notice that coal releases more heat than charcoal. This means that the chemical potential energy in coal is higher than that of charcoal.
Combustion or burning occurs when a substance reacts with oxygen. This reaction is highly exothermic and releases high amounts of energy in the form of heat, light and sound. The amount of energy released depends on the potential chemical energy stored in the substance.
Potential chemical energy is the energy stored in a combustible substance that gets converted to heat, light and sound energy while the substance burns. The more potential chemical energy a substance has, the more energy it expels while burning.
Hence, while burning coal and charcoal, coal will release more heat energy because its potential chemical energy is higher than that of charcoal.
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a compound differs from a mixture in that a compound always has : a. a maximum of two components. c. a definite composition. b. a heterogeneous composition. d. at least three components
Compounds are formed by the combination of two or more molecules. A compound differs from a mixture as the former has a definite composition. Thus, option c is correct.
What are compounds, and mixtures?Compounds are said to be substances that have been composed of various identical molecules bonded together by chemical bonds. They are homogenous substances that have fixed ratios ad proportions.
Mixtures are substances composed of various substances linked by the physical interactions that vary in composition and can be homogenous and heterogeneous.
Therefore, option c. the compounds have fixed composition, unlike the mixtures.
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the malonic ester synthesis is a method for preparing carboxylic acids from alkyl halides. for each of the carboxylic acid products, draw the structure of the alkyl bromide that would be used in its synthesis. alkyl bromide a an arrow with three steps points to a carboxylic acid bonded to c h 2 bonded to a 5 carbon ring. step 1 is diethyl malonate with sodium ethoxide in ethanol. step 2 is n a o h and water. step 3 is h 3 o plus and heat. alkyl bromide b
Alkyl halides are also known as haloalkanes. Halogen atoms have replaced one or more hydrogen atoms in an alkane to form compounds known as alkyl halides (fluorine, chlorine, bromine, or iodine).
structural characteristics of alkyl bromideAlkyl halides are halogen-substituted alkanes in which a halogen atom, such as a fluorine, chlorine, bromine, or iodine, is used in place of one or more hydrogen atoms in an alkane. An alkyl halide has a link between the carbon atom and the halogen atom, which is sp3-hybridized and has a tetrahedral form.Alkyl halides have no colour when they are present in their purest form. However, when bromides and iodides are exposed to light, they become coloured. Many volatile halogen substances smell delicious. At normal temperature, gases of methyl chloride, methyl bromide, ethyl chloride, and certain chlorofluoromethanes exist.learn more about alkyl bromide here
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Which two words from the paragraph help
you understand the meaning of marine?
A "China" and "Japan"
B "coastal" and "seaweed"
C centuries" and "people”
D. superfood" and "studies”
if 20cm3 of 0.125 moldm-3 of tetraoxosulphate(vi) acid solution reacted with a solution of sodium hydroxide, calculate the amount, in moles of sodium hydroxide required for a complete reaction
The amount of sodium hydroxide required to complete the reaction is 0.005 moles.
What is mole?Mole can be defined as a standard scientific unit for measuring large qualities of very small entities such as atom , molecules etc,
Moles can be calculated as mass of substance divided by mass of one mole.
1cm3 = 0.001 dm3
20cm3 = 0.02 dm3
To calculate amount of mole of sodium hydroxide first we have to calculate mass of tatraoxosulphate.
Molarity = mass/ volume
Mass = molarity x volume = 0.125 x 0.02 = 0.0025
2NaOH + H2SO4 -> Na2SO4 + 2H2O
Amount of moles of NaOH = 2 x mass of tatraoxosulphate
= 2 x 0.0025 = 0.005 moles
Thus, the amount of sodium hydroxide required to complete the reaction is 0.005 moles.
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The gaseous state of a substance is due to:
A) the strong bonds between particles
B) the attractions between electrostatically charged particles
C) the high inertia of the small particles
D) the high inertia of the large particles
E) the high-speed motion of particles
Answer:
A the strong bonds between particles.
Explanation:
this is because in solids we say that they have a weak boling point due to the strong bond that makes it hard to melt
if the bonds of a reactant molecule break so that simpler molecules, atoms or ions form, the reaction is an exchange reaction.
If the bonds of a reactant molecule break so that simpler molecules, atoms or ions form, the reaction is an exchange reaction called decomposition reaction
What is a decomposition reaction ?Decomposition reactions occur when complex chemical entities split apart into smaller components. Decomposition reactions often demand energy input. For instance, the thermal breakdown of potassium chlorate (KClO3) is a typical technique used in laboratories to generate oxygen gas.
Heat-induced breakdown is known as thermolysis. Decomposition caused by electricity is known as electrolysis. Decomposition brought on by light is referred to as photolysis. Heat-induced chemical reaction when one material splits into two or more compounds.The opposite of a combination reaction is supposedly a decomposition reaction. A chemical decomposes into two or more components in a decomposition reaction, whereas in a combination reaction, two or more substances combine to create new molecules while also releasing energy.Learn more about Decomposition reaction here:
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someone please help me figure out how many significant figures are present
2.020 × 10⁻²⁵ has four significant figures and 5.00 × 10²⁷ has three significant figures; correct option is A.
What is the number of significant figures in the given numbers?Significant figures are ways of expressing numbers in approximations such that the number of digits which are considered significant in a given number is stated.
Significant figures are used in approximation of numbers.
Some rules for determining significant figures are given below:
1. All non-zero numbers are significant2. Zeros that occur between two non-zero digits are significant3. Zeros in front of non-zero digits known as leading zeros are not significant4. Zeros after non-zero digits to the right of the decimal are significant.5. Zeros after non-zero digits in a whole number with the decimal shown are significant. 6.Zeros after non-zero digits in a whole number with no decimal shown are not significant.From the above rules:
2.020 × 10⁻²⁵ has four significant figures.
5.00 × 10²⁷ has three significant figures.
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The volume of a container is found to be 38. 5 in3. What is the volume in units of cm3?
The volume of a container is found to be 38. 5 in3. What is the volume in units of cm3?
Explanation:
631cm^3
Rock salt is a mixture of salt sodium chlorine and sand describe how you separate rocksalt to obtain salt crystals and pure dry sand. This question is worth 6 marks so please fill enough points
Answer:
pour the rock salt mixture through a filter made from paper and allow the liquid to filtrate
Explanation:
Separating Sand and Salt
Probably the easiest method to separate the two substances is to dissolve salt in water, pour the liquid away from the sand, and then evaporate the water to recover the salt.
how many electrons can an atoms third energy level hold
Filtration is useful for separating: (1 point)
O solids from liquids or gases
compounds
O
O liquids from liquids
O solutions
Filtration is useful for separating solids from liquids or gases compounds (option A).
What is filtration?Filtration is the act or process of filtering or in chemistry, it is the mechanical separation of a liquid from the undissolved particles floating in it.
Filtration is a common separation technique employed in chemistry for the partitioning of an undissolved solid from a liquid solvent.
For example; when a mixture of sand and water is filtered, the sand stays behind in the filter paper as the residue while the water passes through the filter paper to become the filtrate.
Therefore, it can be said that filtration is useful for separating solids from liquids or gases compounds.
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Answer:
Solids from liquids or gases
Explanation:
Connexus
A student measures the mass of a solution before and after a chemical reaction takes place. In both cases the students measures the mass to be 50. 25 g on an electronic balance with an uncertainty of 0. 05 g. The student realizes that the ranges of uncertainty for each measurement overlap exactly. Which claim can the student make?.
The student can claim: We can’t know for sure whether or not the mass changed, but it seems reasonable to claim that the mass did not change, given that the ranges of uncertainty overlap.
Since the student used the same electronic balance with an uncertainty of 0.05g to measure the mass of the solution before and after chemical reaction, the conclusion is that the masses are the same within the uncertainty of the balance.
+- value is uncertainty value of measurement.
Accuracy is the closeness of a measurement to the true value.
Balance is an instrument for comparing the mass of two bodies.
The percent error is an error between an observed value and the true value of a measurement.
Percent Error = (Actual Value - Estimated Value / Actual Value) × 100%
There are three types of error in chemistry: gross errors, random errors and systematic errors.
Missing options:
The mass definitely stayed the same because the measurement of 50.25 g was obtained each time.
The mass definitely stayed the same because the ranges of uncertainty overlap exactly.
We can’t know for sure whether or not the mass changed, but it seems reasonable to claim that the mass did not change, given that the ranges of uncertainty overlap.
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Write formulas for each of the following ionic compounds
1: aluminum iodide
2: Silver oxide
3: potassium nitride
4: calcium phosphide
5: magnesium fluoride
Answer:
AlI3
Ag2O
k3N
Ca3(PO4)2
MgF2
Three solutions of ph 4. 00, ph 7. 00 and ph 10. 00 are used to calibrate a ph meter. These solutions are known as.
These solutions used to calibrate a pH meter are known as pH buffer.
A buffer can be defined as a substance that prevents the pH of a solution from changing by either releasing or absorbing H⁺ in a solution.
Buffer is a solution that can resist pH change upon the addition of an acidic or basic components and it is able to neutralize small amounts of added acid or base, pH of the solution is relatively stable.
pH (potential of hydrogen) is a numeric scale used to specify the acidity or basicity of an aqueous solution:
When pH is less than seven (pH<7), solution is acidic.
When is equal seven (pH = 7), solution is neutral.
When pH is greater than seven (pH > 7), solution is basic.
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Select all of the particle diagrams that represent a pure substance.
As ,in diagram D we can see that there are only one type of atoms are joined, so they are pure substances. The particle of diagrams that represent a pure substance is Option D.
What is Pure Substance ?The substance which is made up of only one kind of particle and cannot be separated into other kind of matter is called Pure substance.
Example: Gold metal, sugar, salt, copper wire, diamond etc.
These substance are of two types
ElementscompoundsHow to find which substance is pure from diagram?So, we are going to find out the pure substance from the below diagrams. All other are mixtures having different kind of element.
Thus from the above conclusion we can say that the option D represents pure substance.
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the equation for reaction between calcium carbonate and hydrochloric acid is shown. CaCO3 + 2HCl —> CaCl2 + H2O + CO2 how many moles of calcium carbonate will give 24 cm3 of carbon dioxide when reacted excess of the acid?
Answer:
0.001 mole
Explanation:
I attached my answer
fertilizer is sold in 100 pound bags labelled with the amount of nitrogen ( n), phosphoric acid ( p2o5), and potash ( k2o) present. the mixture of these nutrients varies from one type of fertilizer to the next. for example, a pound bag of vigoro ultra turf fertilizer contains pounds of nitrogen, pounds of phosphoric acid, and pounds of potash. another type of fertilizer, parker’s premium starter, has pounds of nitrogen, pounds of phosphoric acid, and pounds of potash per pounds. determine the amount of each type required to yield a mixture containing the pounds of nitrogen, pounds of phosphoric acid, and pounds of potash.
The amount of each type required to yield a mixture containing the pounds of nitrogen, pounds of phosphoric acid, and pounds of potash is y = 5 bags, x = 3 bags.
What are fertilizers?Fertilizers are any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients.
177 pounds = 29x + 18y (1)
Where x is bags of Vigor Ultra Turf fertilizer and y are bags of Parkers Premium Starte-
For P₂O₅:
134 pounds = 3x + 25y (2)
For K₂O:
42 pounds = 4x + 6y (3)
Replacing (1) in (2):
134 = (531/29 - 54y/29) + 25y
3355/29 = 671y/29
Thus, y = 5 bags, x = 3 bags.
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will a hurricane lose strength if the winds become strong? and why?
No, hurricane won't loose strength when the winds are strong.
It's because If wind conditions are okay, the storm becomes a hurricane. This heat energy is the energy for the storm. And the warmer the water, the further humidity is in the air. And that could mean bigger and stronger hurricanes.
Hurricanes increases their speed their strength because Warmer ocean face temperatures consolidate tropical storm wind pets.
These are the top 3 factors for hurricane development
Warm ocean water
Wind shear
humidity content
If hurricanes snappily lose strength as they move over land it's only because of the Friction with Land.
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________ can be
made in the field or in the laboratory.
Answer:
observations
Explanation:
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The speedometer at right displays a car's speed in miles per hour. (65 mph)
What is the car's speed in km/h? (1 km = 0.62 mile)
Answer:
57 mph 91.73 kph
58 mph 93.34 kph
59 mph 94.95 kph
60 mph 96.56 kph
is the answer
Explanation:
20 things before cooking
Answer:
step 1- wash the rice cooker
step2-
How many valence electrons does Neon (atomic #10) have? (1pt)
*
1 point
1
7
8
10
8 valence electron are present in Neon .
What is valence electron?The electrons in an atom's outermost shell, or energy level, are called valence electrons.
The amount of electrons an atom has in its outermost valence shell determines how it bonds with other atoms.
The Periodic Table groups together elements whose atoms have the same number of valence electrons for this reason.
Neon, with a Z=10, possesses eight valence electrons. Due to its closed-shell structure, neon is extremely difficult to oxidise and decrease.
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The molar mass of hydrochloric acid is 36.461 g/mol. If 1.2 g of HCl are dissolved in 25ml of solution, what is the molarity?
You have 250ml of a 0.75 M lithium nitrate solution. How many moles are in it?
If you want to make a 0.25 M solution of sodium sulfate, and you use 0.75 L of water, how many moles of sodium sulfate should you add?
You have 56 mL of a 1.1 M lithium iron (II) phosphate solution. How many moles are in it?
If you want to make a 6.0 M of HCl, and you use 2.00 L of water, how many moles of HCl should you add?
use the formula M=n/V, where M=molarity, n=moles of solute, V= volume in litres
1.3M
0.02 mols
0.188 mols
0.062 mols
12 mols
The half life of a radioactive element is 20 days. How many days will it take for the radioactive sample to decay to 1/8 its size?
Answer:
it will be 60 day
Explanation: