why do we need to rinse the mouth before collecting the saliva
what does the period number on the periodic table tell us?
Answer:
The period number on the Periodic table tells you the total number of orbits that the atom will have. In other words, the period number indicates the number of energy levels (or energy orbit) of an atom. For example, 1st period indicates that these elements possess 1 energy shell (or energy orbit).
Explanation:
Question 21 of 25
Which of the following are elements in this equation:
2Mg(s) + O2 (9) ► 2Mgo (s)?
Check all that apply.
A. g
B. Mg
C. O
D. S
Answer: Mg and O
Explanation: just took the test. Trust
In the Caribbean countries, general election is usually held every _ years
it is held every 4-5 years
What volume of water is needed to make 5.41 M solution with 47.71 moles of HCL?
Answer:
0.113 liters
Explanation:
5.41 M / 47.71 moles = 0.113 liters
Blank O2 + blank Mg arrow blank MgO
Select the coefficients that balance the equation:
MgO *
A) 1,1,1
B) 1,2,2
C) 2,3,4
D) 1,4, 2
Answer:
its a
Explanation:
a
What is the mass of disulfur pentoxide (S2O5)?
Answer: What is the mass of disulfur pentoxide (S2O5)?
Explanation:144.14g/mol
please help! due soon!
Answer:
I think it's
there are the same number of molecules on each side of the equation, then a change of pressure makes no difference to the position of equilibrium
classify the following alcohols as primary secondary and tertiary alcohols?
Help please help me!!!!!
Answer:
B. 460 NM
Explanation:
THAT THE ANSWER
How many moles of aluminum are in 54 grams
During Photosynthesis, what does a producer take in from the air?
Which of the following would be the best caption for this image?
A
The Coriolis effect causes convection cells of air to circulate through the atmosphere.
B
The pattern of ocean currents is identical to the pattern of wind currents.
C
Uneven heating of land and water causes winds to blow in different directions during the daytime and night time.
D
There are six bands of global wind currents. These bands of wind currents are caused by convection cells created by the warming and cooling of air.
In which type of chemical reaction would two reactants join together and form one product
Answer:
Synthesis Reaction
Explanation:
A synthesis reaction occurs when two or more reactants combine to form a single product. In a decomposition reaction, one reactant breaks down into two or more products. This is the reverse of a synthesis reaction. Replacement reactions occur when elements switch places in compounds.
Drag the slider from January to December. Based on what you observe, do you think Barcelona has large temperature changes throughout the year?
Answer:
Yes.
Explanation:
Yes, I think that Barcelona has large temperature changes throughout the year because Barcelona has minimum temperature of 33°F in winter season and maximum temperature of 88°F in summer season. In Barcelona, the summers are short, warm, and humid while on the other hand, the winters in Barcelona are long, cold, and partly cloudy. The temperature typically varies from 40°F to 83°F and is rarely goes below 33°F or above 88°F.
how many atoms are in 4.5 moles of Al?
Explanation:
4.5×6.022×10²³
27.099×10²³
According to Avogadro's number, there are 27.10×10²³ atoms in 4.5 moles of Al.
What is Avogadro's number?Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.
It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .
According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.
Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number.As 1 mole =6.023×10²³ atoms , thus,4.5 moles =4.5×6.023×10²³ = 27.10×10²³ atoms.
Thus, there are 27.10×10²³ atoms in 4.5 moles of Al.
Learn more about Avogadro's number,here:
https://brainly.com/question/11907018
#SPJ2
What is a state function?
Which of the following statements describes a REACTANT and where they are
chemical equation?
The chemicals that
you begin with, found
on the right side of the
equation
The chemicals that The chemicals that The chemicals that
you begin with, found end with, found on the you enyi with, found or
on the left side of the left side of the the right side of the
equation
equation
equation
Music of
Answer: The statement, chemicals that you begin with found on the left side of the equation, describes reactant and where they are in a chemical equation.
Explanation:
An equation that includes symbolic formulas and represents chemical reaction between the substances initially present forming new substances is called a chemical equation.
For example, [tex]N_{2} + 3H_{2} \rightarrow 2NH_{3}[/tex]
Here, substances [tex]N_{2}[/tex] and [tex]H_{2}[/tex] are the reactants. Reactants in a chemical equation are always present on the left side as these are the chemicals we begin with.
Also here, [tex]NH_{3}[/tex] is the product. Product(s) in a chemical equation are always present on the right side as these are the chemicals we end with.
Thus, we can conclude that the statement, chemicals that you begin with found on the left side of the equation, describes reactant and where they are in a chemical equation.
You are given 250 mL of a 12.0 M solution of KNO3. To obtain a 5.0 M, to what volume does the solution need to be diluted to?
600 ml
104.17 mL
0.24 mL
60 mL
Answer:
600 mL
Explanation:
molarity 1 * volume 1 = molarity 2 * volume 2. So this means 12 * 250 = 3000 and divide that by 5 to get 600 mL.
5). At what temperature (K) will 0.854 moles of neon gas occupy 12.3 L at 1.95
atmospheres?
Answer:
338.38 K
Explanation:
Applying,
PV = nRT............... Equation 1
Where P = pressure, V = Volume, R = Temperature, n = number of moles, T = temperature.
Make T the subject of the equation,
T = PV/nR............. Equation 2
From the question,
Given: P = 1.95 atm, V = 12.3 L, n = 0.854 moles
Constant: R = 0.083 L.atm/K.mol
Substitute these values into equation 2
T = (1.95×12.3)/(0.854×0.083)
T = 338.38 K
Which of the following statements about alkynes is incorrect?
Alkynes are unsaturated hydrocarbons.
Alkynes have triple bonds.
Alkynes are saturated hydrocarbons.
Alkynes have carbon atoms.
Answer:
Alkynes are saturated hydrocarbons
Explanation:
Alkynes are groups of hydrocarbons that have the general formula of {Cn H2n - 2}. They have a triple carbon to carbon bond (C≡C) in their structure. Ethyne (HC≡CH) is the first member of the alkyne series.
Alkynes like alkenes are unsaturated hydrocarbons because of their triple and double carbon bonds respectively. Unsaturated hydrocarbons do not have a complete hydrogen atom in their structural composition. Hence, the statement that "Alkynes are saturated hydrocarbons" is FALSE.
What is the mass number of an element?
please helpppp!!!!!!!!!!!
Answer:
If a substance can be dissolved it is called soluble.
if a substance cannot be dissolved it is called insoluble
Based on information from the periodic table, which statement is true for the
element cobalt?
Answer: (A) a cobalt atom contains 27 protons, and most cobalt atoms contain 32 neutrons.
Explanation: just answered the question and that was the correct answer
Answer: The answer is : A cobalt atom contains 27 protons and MOST neutral cobalt atoms contain 32 electrons
Explanation: I took the test
11
Cr2O3 + 2Al → 2Cr + Al2O3
Chromium is produced by reacting its oxide with aluminum. If 76 g of Cr2O, and 27 g of Al completely react to form 51 g of Al2O3. how many grams of Cr are formed?
Answer:
Deci trebuie sa te aplici cu 2 din3 pe suprafata pamanyului chinez
Explanation:
Deci 1287+2086+2762+7:5
If a solution has a [H+] of 9.3x10-11, what is the pH?
Answer:
10.03Explanation:
The pH of a solution can be found by using the formula
[tex]pH = - log [ {H}^{+} ][/tex]
From the question we have
[tex]ph = - log(9.3 \times {10}^{ - 11} ) \\ = 10.0315...[/tex]
We have the final answer as
10.03Hope this helps you
Using the example of an ambulance, explain the Doppler Effect. Infer why the doppler effect can or cannot occur in all waves. PLEASE ANSWER ILL PICK BRAINLEIST TO THE FIRST ACTUAL ANSWER
Answer:
When the ambulance is coming towardss you the waves are smushed together and sound higher pitched but then it passes you and when tracveling away the waves are scretched out so the whee whoo sounds lower and that is because of the doppler effect
I need help on deciding which one i should get
Answer:
I would say the purple one!
Explanation:
what do mars, pluto, and Jupiter have in common (science) in 8th grade.
Answer:
they are all planets
Explanation:
-
(11) Deduce the number of dyes in food colouring H.
(iii) Suggest why food colouring F does not move during the experiment.
(iv) Explain which two food colourings contain the dye that is likely to be the most soluble the solvent.
(b) Determine which food colouring contains a dye with R, value closest to 0.67
Show your working.
Answer:
(ii) 1 dye
(iii) Food coloring F is insoluble in the solvent
(iv) 'E' and 'H'
(b) Food colouring G
Explanation:
Paper chromatography principle is based on the rates of migration of chemicals across a sheet of paper which are different and it consists of a stationary phase such as the water in the paper and a mobile phase such as the solvent resulting in the partitioning of the components of the mixture across the paper
The solution components are positioned to start in one place from where they migrate and separate out on the chromatography paper
(ii) The number of components into which the food colouring 'H' separates into = 1
Therefore, the number of dyes in food colouring 'H' = 1 dye
(iii) Food coloring 'F' does not move because it is insoluble in the solvent, which is the mobile phase
(iv) The food colouring that contains the dye that is likely to be most soluble in the solvent are does for which the dyes travel furthest, which are;
Food coloring 'E' and 'H'
(b) Using a similar question solution found on 'tutor my self' website, we have;
The [tex]R_f[/tex] values are given as follows;
[tex]R_f = \dfrac{Distance \ moved \ by \ dye}{Distance \ moved \ by \ solvent}[/tex]
The distance moved by the solvent = 5 units
The distance moved by dyes in food colouring 'E' and 'H' = 4 units
The distance moved by dye in food colouring 'G' = 3.3 units
The distance moved by the second dye in food colouring 'E' = 2.7 units
By inspection, we get;
[tex]R_f[/tex] dye in food colouring 'G' = 3.3/5 = 0.66,
Therefore, the dye with [tex]R_f[/tex] value closest to 0.67 is the dye in food colouring 'G'.