Answer:
D
Explanation:
this is because the number of protons is always equal to the number of electrons of an atom
Which of the following is the smallest?
A) salt grains
B) water molecule
C) human red blood cells
D) C. Difficile Bactria
Answer:
it's either a or b not c or d. there you go hope I helped
Explanation:
salt grains are very small, just like water molecule. so yea, hope I helped you out whoever you are.
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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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 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:
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
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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________ can be
made in the field or in the laboratory.
Answer:
observations
Explanation:
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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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How many bonds are broken in the balanced reaction of the combustion of nitric oxide.
Answer:3
Explanation:
In the balanced reaction of the combustion of nitric oxide (NO), two bonds are broken.
Nitric oxide (NO) is composed of a nitrogen atom bonded to an oxygen atom. During combustion, NO reacts with oxygen (O2) to form nitrogen dioxide (NO2). The balanced chemical equation for this reaction is:
2 NO + O₂ → 2 NO₂
In this reaction, there are two molecules of nitric oxide (NO) on the left-hand side of the equation. Each nitric oxide molecule has one nitrogen-oxygen bond, so there are a total of two bonds in the reactants.
On the right-hand side of the equation, there are two molecules of nitrogen dioxide (NO2). Each nitrogen dioxide molecule has two nitrogen-oxygen bonds, so there are a total of four bonds in the products.
To balance the equation, two nitric oxide molecules are needed to produce four nitrogen dioxide molecules. This means that during the reaction, two nitrogen-oxygen bonds are broken in the reactants, and four new nitrogen-oxygen bonds are formed in the products.
In summary, in the balanced reaction of the combustion of nitric oxide, two bonds are broken.
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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”
A child attending daycare is prescribed 750 mg of an antibiotic for 10 days. The drug may be dosed in several ways and is available in two concentrations. Which dosing regimen will the provider consider to best assure drug adherence? group of answer choices 375 mg of a 250 mg/5 ml solution po twice daily 250 mg of a 250 mg/5 ml solution po three times daily 250 mg of a 500 mg/5 ml solution po three times daily 375 mg of a 500 mg/5 ml solution po twice daily
The best kind of prescription for the child is 250 mg/5 ml solution po three times daily.
What is a dose?The term dose has to do with the quantity or amount of the drug that a patient is required take. We must know that a drug is a chemical and being a chemical, there must be a specified amount of it that has to be taken per day.
We know that the dose of the drug that is given to a patient is sometimes in proportion to the degree of symptoms that the patient is feeling. In this case, we can see that the drug is given in more than one dose. We now have to find out the correct dose of the drug that is required in this case.
Let us look at the drug, we are told that a child attending daycare is prescribed 750 mg of an antibiotic for 10 days. The best kind of prescription for the child is 250 mg/5 ml solution po three times daily.
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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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how many electrons can an atoms third energy level hold
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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while water is boiling, it absorbs 2257 kj of heat per kilogram of water. this takes place at a constant temperature of 100°c. what is the entropy change of 10 kg of water while it boils? (be careful of your energy units). (1 point)
The entropy change is 6.051 x 10^4 J/K
Given:
mass of water = 10 kg
latent heat of boiling = 2257 kj
constant temperature = 100°c
To Find:
entropy change of 10 kg of water
Solution:
entropy change = mass*latent heat of boiling/temperature
= 10×2257×1000/(273+100) K
= 22,570,000/373K = 6.051 x 10^4 J/K
Hence, entropy change is 6.051 x 10^4 J/K
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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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I NEED HELP ASAP PLEASE !!
Answer:
The last option. Because it's not a curate or precise on the dot.
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
Mrs. Richardson performed an experiment on how the type of music affected plant growth. She sets up an experiment playing rock music, jazz music, country music, and rap music to fern plants. She also has a fern plant that she puts in a quiet room. She measures how tall the plants have grown after 4 weeks. They all received the same amount of water and light.
What is the dependent variable?
a
Rock, jazz, country, rap, and no music
b
Amount of water and light
c
Type of music
d
Plant growth
The dependent variable in this type of experiment is referred to as the Plant growth and is therefore denoted as option D.
What is Dependent variable?This refers to a type of variable whose value will change depending on the value of another variable which is referred to as the independent variable. It is also referred to the variable which is usually tested or measured when an experiment is done by scientists.
In this case, we were told that the plant were exposed to different criteria such as the music types and the constants such as light and water and the effect on the plant growth will be measured after sometime.
Since the parameter to be measured is the plant growth then it is referred to as the most appropriate choice for dependent variable.
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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
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:
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
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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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
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
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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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:
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.