Answer:
Counting the number of colonies that arise on a pour plate can calculate the concentration by multiplying the count by the volume spread on the pour plate. Direct counting methods are easy to perform and do not require highly specialized equipment, but are often slower than other methods
Explanation:
I hope it will help you
what are some of the uses of halogens?
Answer:
Halogens are used in, water and sanitation, plastics, pharmaceutical, pulp and paper, textile, military and oil industries. Bromine, chlorine, fluorine and iodine are chemical intermediates( bleaching agents and disinfectants). Chlorine is used to purify water. Chlorine also is part of salt, sodium chloride, which is one of the most widely used chemical compounds. Fluorine is used in fluorides, which are added to water supplies to prevent tooth decay.
hopes this helps~
Answer:
What are some uses of halogen elements? Chlorine is used to purify water. Chlorine also is part of salt, sodium chloride, which is one of the most widely used chemical compounds. Fluorine is used in fluorides, which are added to water supplies to prevent tooth decay.
Explanation:
Halogen, any of the six nonmetallic elements that constitute Group 17 (Group VIIa) of the periodic table. The halogen elements are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts). They were given the name halogen, from the Greek roots hal- (“salt”) and -gen (“to produce”), because they all produce sodium salts of similar properties, of which sodium chloride—table salt, or halite—is best known.
Because of their great reactivity, the free halogen elements are not found in nature. In combined form, fluorine is the most abundant of the halogens in Earth’s crust. The percentages of the halogens in the igneous rocks of Earth’s crust are 0.06 fluorine, 0.031 chlorine, 0.00016 bromine, and 0.00003 iodine. Astatine and tennessine do not occur in nature, because they consist of only short-lived radioactive isotopes.
what is the atomicity of Sulphur?
Answer:
the atomicity of sulphur is 8
Explanation:
hope it helps
Why is the average atomic mass used when calculating grams of a
substance?
A. The average atomic mass is known to more significant figures.
B. The elements in the substance are mixtures of their isotopes.
C. The exact weights of the isotopes are not known.
D. The number of isotopes in the sample is constantly changing.
Answer:
B. The elements in the substance are mixtures of their isotopes.
Write your question here (Keep it simple and clear to get the best answer) what are the uses of alkane
Answer: Alkanes are important raw materials of the chemical industry and the principal constituent of gasoline and lubricating oils. Natural gas mainly contains methane and ethane and is used for heating and cooking purposes and for power utilities (gas turbines).
phosphorus react with carbon
Answer:
Phosphorus atoms can bond with oxygen atoms to form ester groups. These can bond with carbon atoms, yielding a large number of organic phosphorus chemicals. These are found in many important biological processes
Explain the steps you would follow to make 500 mL of a 0.3 M solution of sucrose
(C12H22011) in the lab.
Answer:
see explanation
Explanation:
Solutions are prepared from one of three solute sources ...
- solid solute from manufacturer,
-liquid solute from manufacturer,
-stock concentrate of solute for dilution to lower concentrations.
In this problem, sucrose is a stock solid with a formula mass of 342.3 grams/mol. The amount of solid needed can be determined using the formula:
mass of solute needed (grams) = (Molarity needed x Volume needed in Liters x formula weight) / (decimal fraction purity of stock solid)
Molarity needed = 0.3M
Volume needed = 500 ml = 0.500 liters
Formula weight = 342.3 grams/mole
Purity factor (assumed) = 100% = 1.00 (should be posted on stock bottle label) For example, a 95% pure stock solid => purity factor of 0.95.
∴ grams of sucrose needed = (0.3M*)(0.500L)(342.3g/mole)/(1.00) =51.345 grams sucrose.
Measure 51.345 grams of sucrose into mixing vessel and add solvent water up to, but not to exceed 500 ml total volume. Mix until homogeneous.
Is the graph more accurate with more atoms or less atoms?
Answer:
I would guess more atoms? but there is no graph attached
please help asap!!!!!!!!
The two waves in the diagram are occupying the same place at the same time. At what time will the interfering waves have an amplitude of zero? 1.0 3.0 4.0 7.0 Mark this and return
Answer: It’s 4.0
Explanation: I just took the test and got it right:)
mendeleev's periodic table is studied even though it is considered to be defective
Answer:
This is because Mendeleev arranged the elements in order of increasing relative atomic mass.
Explanation:
Dmitri Mendeleev is one of the scientists that contributed to the development of periodic table in chemistry. He was able to organise elements into rows according to their atomic mass and into columns based on chemical and physical properties. This is the main reason why his periodic table is still studied even though it has some defects which include:
--> Grouping of elements that are not similar chemically: For example Copper and Silver bear no resemblance with the alkali metals, but they have been placed together in the first group.
--> Position of isotopes: According to his periodic table: Isotopes of an element must be given separate places in the periodic table because they have different atomic masses.
--> Electronic arrangement of elements: It failed to explain the electronic arrangement of elements.
--> Separation of chemically similar elements:
Elements that are chemically similar such as Gold and Platinum have been placed in separate groups.
What is an air mass? Where on Earth might you find a hot and dry air mass?
An air mass is a volume of air whose temperature and humidity are specified. Many hundreds or thousands of square miles are covered by air masses, which adjust to the properties of the land underneath them.
What is an air mass ?An air mass is a volume of air whose temperature and humidity are specified. Many hundreds or thousands of square miles are covered by air masses, which adjust to the properties of the land underneath them. Latitude and their continental or marine source regions are used to categorize them.
There is a temperature and air pressure differential. Storms are caused by abrupt changes in the weather. Two natural wind patterns come into conflict.
The hot and dry continental tropical (cT) air mass is prevalent over subtropical and tropical continents. The world's largest deserts, such the Sahara, Arabian, and Australian, are important source areas.
Thus, Latitude and their continental or marine source regions are used to categorize them. An air mass is a volume of air whose temperature and humidity are specified.
To learn more about an air mass, follow the link;
https://brainly.com/question/28709357
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Can someone help me with this question ASAP
H2S04+CaCO3—>Ca S04+H20 +CO 2
help me balance it
Answer:
It's already balanced.
Explanation:
REACTANTS PRODUCTS
H = 2 H =2
S = 1 S = 1
O = 7 O = 7
Ca = 1 Ca = 1
C = 1 C =1
Had beryllium and calcium already been discovered
Answer:
Yes
Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. ... Notable gemstones high in beryllium include beryl (aquamarine, emerald) and chrysoberyl.
Calcium is a mineral that is necessary for life. In addition to building bones and keeping them healthy, calcium enables our blood to clot, our muscles to contract, and our heart to beat. About 99% of the calcium in our bodies is in our bones and teeth.
A 2.50 L container is filled with 175 g of argon; a. If the pressure is 10 atm, what is the temperature ? b if the temperature is 22K, what is the pressure ?
Answer:
A. 70 K
B. 3.16 atm
Explanation:
We'll begin by calculating the number of mole in 175 g of Ar. This can be obtained as follow:
Mass of Ar = 175 g
Molar mass of Ar = 40 g/mol
Mole of Ar =?
Mole = mass / molar mass
Mole of Ar = 175 / 40
Mole of Ar = 4.375 moles
A. Determination of the temperature.
Mole of Ar (n) = 4.375 moles
Volume (V) = 2.50 L
Pressure (P) = 10 atm
Gas constant (R) = 0.0821 atm.L/Kmol
Temperature (T) =?
PV = nRT
10 × 2.5 = 4.375 × 0.0821 × T
25 = 4.375 × 0.0821 × T
Divide both side by (4.375 × 0.0821)
T = 25 / (4.375 × 0.0821)
T ≈ 70 K
B. Determination of the pressure.
Mole of Ar (n) = 4.375 moles
Volume (V) = 2.50 L
Temperature (T) = 22 K
Gas constant (R) = 0.0821 atm.L/Kmol
Pressure (P) =?
PV = nRT
P × 2.5 = 4.375 × 0.0821 × 22
Divide both side by 2.5
P = (4.375 × 0.0821 × 22) / 2.5
P = 3.16 atm.
Pls help!!!
You are given a type of element by a teacher and she asks you to identify it.What should you do?Explain your answer
Answer:
NAO SRESONDEPORR PQUEOU BUOBRRRA IGAD THCAAUSEI
Explanation:
A gas has an initial volume of 52.3 L at 273 Kelvin. What is its temperature when the volume reaches 145.7 L?
Answer:
[tex]\boxed {\boxed {\sf 761 \ K}}[/tex]
Explanation:
We are asked to find the new temperature of a gas after a change in volume. We will use Charles's Law, which states the volume of a gas is directly proportional to the temperature. The formula for this law is:
[tex]\frac {V_1}{T_1}= \frac{V_2}{T_2}[/tex]
The volume is initially 52.3 liters at a temperature of 273 Kelvin.
[tex]\frac {52.3 \ L}{273 \ K}= \frac{V_2}{T_2}[/tex]
The volume reaches 145.7 liters at an unknown temperature.
[tex]\frac {52.3 \ L}{273 \ K}= \frac{145.7 \ L }{T_2}[/tex]
We are solving for the new temperature, so we must isolate the variable T₂. Cross multiply. Multiply the first numerator and second denominator, then the first denominator and second numerator.
[tex]52.3 \ L * T_2 = 273 \ K * 145.7 \ L[/tex]
Now the variable is being multiplied by 52.3 liters. The inverse of multiplication is division. Divide both sides by 52.3 L.
[tex]\frac {52.3 \ L * T_2 }{52.3 \ L}=\frac{ 273 \ K * 145.7 \ L}{52.3 \ L}[/tex]
[tex]T_2=\frac{ 273 \ K * 145.7 \ L}{52.3 \ L}[/tex]
The units of liters cancel.
[tex]T_2=\frac{ 273 \ K * 145.7 }{52.3 }[/tex]
[tex]T_2 = 760.5372849 \ K[/tex]
The original measurements have at least 3 significant figures, so our answer must have 3. For the number we found, that is the ones place. The 5 in the tenths place tells us to round the 0 up to a 1.
[tex]T_2 \approx 761 \ K[/tex]
When the volume reaches 145.7 liters, the temperature is 761 Kelvin.
Which letter in the diagram represents the transition from liquid to gas?
A
B
C
D
Answer:
D
Explanation:
B is solid and liquid while D is liquid and gas
Answer:
Option ( D) is correct
The phase transition occurs at 100o C (the normal boiling point of water). Liquid water becomes water vapor or steam when it enters the gaseous phase.
Explanation:
A heating curve graphically represents the phase transitions that a substance undergoes as heat is added to it.
The liquid will begin to boil when enough heat has been absorbed by the solution that the temperature reaches the boiling point, where again, the temperature remains constant until all of the liquid has become gaseous water. At the atmospheric pressure of 1 atm, this phase transition occurs at 100o C (the normal boiling point of water). Liquid water becomes water vapor or steam when it enters the gaseous phase. Use the heat of vaporization ([latex]\Delta H_{vap}[/latex] ) to calculate how much heat was absorbed in this process: [latex]q=m\cdot C_{H_2O(g)}\cdot \Delta T[/latex], where m is the mass of the sample of water.
After all of the liquid has been converted to gas, the temperature will continue to increase as heat as added. Again, the heat added that results in a certain change temperature is given by: [latex]q=m\cdot C_{H_2O(g)}\cdot \Delta T[/latex] . Note that the specific heat capacity of gaseous water is different than that of ice or liquid water.
What is the name of the compound with the formula B2C14?
Answer:
Diboron tetrachloride ---> B2Cl4
please help me with this
Answer:
a. B
b. C
c. A
d. A
e. B
f. -266
g. B and D
Now look at the volcano map what type of boundary tends to give rise to volcanic activity
Answer:
Volcanoes occur primarily on convergent boundaries, specifically oceanic-continental convergent boundaries.
Explanation:
plato
ii.
ci
What is the name of the organic compound
Answer.
Hydrocarbons are compounds that contain carbon and hydrogen only
Explanation:
a. c3H4 methane
b.c3H4.propene
c.c5H8
Can someone help with this
Answer:
I think option (d) is right answer
Answer:
I think that the answer is option(C)
Need help.
Sodium Sulphate crystallises out as Na2SO4.10H2O. It is prepared by titration. 25.0cm^3 aquas of NaOH solution having a concentration of 2.24 mol/dm^3 reacted with H2SO4 to give Na2SO4.10H2O. The molecular mass of Na2SO4.10H2O = 322 grams. Find the % yield of Na2SO4.10H2O.
Answer:
Assuming the mass of Na2SO4.10H2O obtained from the crystallization was: 8.5g
The % yield is 94.3%
Explanation:
Assuming the mass of Na2SO4.10H2O was:
Based on the reaction:
2NaOH + H2SO4 + 8H2O →Na2SO4.10H2O
Where 2 moles of NaOH reacts producing 1 mole of Na2SO4.10H2O
To solve this question we need to find the moles of NaOH added. With the moles and the reaction we can find the moles of Na2SO4.10H2O and its actual theoretical yield. Assuming the mass of Na2SO4.10H2O produced was: 8.5g
we can find the percent yield as follows:
Moles NaOH:
25.0cm³ = 0.0250dm³ * (2.24mol/dm³) = 0.056 moles NaOH
Moles Na2SO4.10H2O:
0.056 moles NaOH * (1mol Na2SO4.10H2O / 2mol NaOH) = 0.028 moles Na2SO4.10H2O
Mass Na2SO4.10H2O:
0.028 moles Na2SO4.10H2O * (322g / mol) = 9.016g Na2SO4.10H2O = Theoretical yield
Percent yield is 100 times the ratio between actual yield:
8.5g / 9.016g * 100 = 94.3%
How long does it take, on average, for one centimetre of soil to form
Which of the following is an oxide which is strongly acidic?
(a) Na2O.
(b) MgO
(c) SiO2.
(d) P2O5.
Answer:
answer of your question is 4th
Explanation:
P205
Draw the structure for :
3,3,4-trimethylhex-2-ene
Answer:
answer is in the picture.
Help me please
The options are
A. Translation
B. Rotation
C. Enlargement
D.reduction
Answer:
C. Enlargement
Explanation:
balance the equation .......qn 5.......help
Answer:
MnO4 + 4 H2C2O4 = Mn + 8 CO2 + 4 H2O
Rank these solutions from the most alkaline (1) to the least alkaline (5).
Define oxidation in terms of election transfer
Explanation:
Is the loss of electrons, gains of oxygen or loss of hydrogen
Answer:
Oxidation is the loss of electrons or an increase in the oxidation state of an atom, an ion, or of certain atoms in a molecule. Reduction is the gain of electrons or a decrease in the oxidation state of an atom, an ion, or of certain atoms in a molecule
