Answer:
Mendeleev arranged the elements in order of increasing relative atomic mass. When he did this he noted that the chemical properties of the elements and their compounds showed a periodic trend. He then arranged the elements by putting those with similar properties below each other into groups.
-- He left gaps for yet to be discovered elements
-- He switched the order of a few elements to keep the groups consistent
-- He was the first scientist to give the periodic law.
the wavelength of a light wave whose frequency 5.0x 10^9 s^-1 is
Answer:
wavelength = 6 cm .
Explanation:
frequency given = 5 x 10⁹ .
wavelength = velocity of light / frequency
= 3 x 10⁸ / 5 x 10⁹
= .06 m
= 6 cm
Element X is a solid that is brittle, lacks luster,and has six valence electrons. In which group on the Periodic Table would element X be found
Answer:
Sulfur?
Explanation:
Sulfur has 6 valence electrons and does not have luster.
Which of the following is true for a gas under conditions of very low temperature? PV ÷ nRT = 1, because all gases behave ideally at very low temperatures. PV ÷ nRT = 1, because the actual volume of the gas molecules becomes considerable. PV ÷ nRT > 1, because the low temperatures speed up the particles. PV ÷ nRT < 1, because particles are unable to overcome intermolecular attractions.
Which phrase describes a feature of a Mercator projection? is least commonly used sizes most features to scale presents longitude lines as parallel shows most accurately near the prime meridian
QUICK
Answer:
presents longitude lines as parallel
Explanation:
The Mercator projection shows longitude lines as parallel, hence greatly distorts sizes and distances near the poles. A useful feature is that a course of constant bearing shows as a straight line.
Answer:
C.) presents longitude lines as parallel
Explanation:
Took it on E2020
What is one way to make stored water safe?
Even though you asked for ONE WAY, I found some other good ways.
1. Thoroughly wash plastic soda bottles or milk jugs with warm, soapy water.
2. Store sealed containers in a dark, dry, and cool place.
3. If after six months you have not used the stored water, empty it from the containers and repeat steps 1 through 3 above.
PLEASE HELP CHEM BABES I HAVE BEEN CRYING FOR A WHILE NOW
1. Calculate the mass of nitrogen dioxide (NO2) present in a 0.831 L container if the pressure is 100 kPa at a temperature of 27 oC. R = 8.31 kPa x L / mol x K. (K = oC + 273).
2. A 33.2 L tank contains 280 g of compressed helium. If the pressure inside the tank is 700.0 kPa, what is the temperature of the compressed gas? You must convert the mass of helium into moles using the molar mass of He. The conversion factor will be 1 mol / molar mass of helium. R = 8.31 kPa x L / mol x K
Answer: See below
Explanation:
1. To calculate the mass, you know you can convert by using molar mass. Since mass is in grams, we can use molar mass to convert moles to grams. This calls for the Ideal Gas Law.
Ideal Gas Law: PV=nRT
We manipulate the equation so that we are solving for moles, then convert moles to grams.
n=PV/RT
P= 100 kPa
V= 0.831 L
R= 8.31 kPa*L/mol*K
T= 27°C+273= 300 K
Now that we have our values listed, we can plug in to find moles.
[tex]n=\frac{(100kPa)(0.831L)}{(8.31kPa*l/molK)(300K)}[/tex]
[tex]n=0.033mol[/tex]
We use the molar mass of NO₂ to find grams.
[tex]0.033mol*\frac{46.005g}{1mol }=1.52 g[/tex]
The mass is 1.52 g.
2. To calculate the temperature, we need to use the Ideal Gas Law.
Ideal Gas Law: PV=nRT
We can manipulate the equation so that we are solving for temperature.
T=PV/nR
P= 700.0 kPa
V= 33.2 L
R= 8.31 kPa*L/mol*K
n= 70 mol
Now that we have our values, we can plug in and solve for temperature.
[tex]T=\frac{(700kPa)(33.2L)}{(70mol)(8.31 kPa*L/molK)}[/tex]
[tex]T=40K[/tex]
The temperature is 40 K.
What would the molecular formula be if lithium and sulfur reacted to form a neutral compound?
Answer:
Li2SExplanation:
Since Lithium gives away one electron, I believe it goes to Sulfur.
Hope this helps! :)
Answer:
Li*2S
Explanation:
ed tell chem
A 14.00-g piece of iron absorbs 1000 joules of heat energy, and its temperature changes from 25°C to 125°C. Calculate the specific heat capacity of iron.
Answer:
THE SPECIFIC HEAT OF IRON IS 0.714 J/g °C
Explanation:
Heat absorbed = 1000 J
Mass of the piece of iron = 14 g
Temeperature changes = ( 125-25)°C= 100°C
specific heat of iron = unknown
To find the specific heat of iron in the question use the formula of heat
Heat = mass * specific heat * temperature change
Specific heat = Heat / mass * temperature change
Specific heat = 1000 / 14 * 100
Specific heat = 1000 / 1400
Specific heat = 0.714 J/g °C
So therefore, the specific heat of iron is 0.714 J/g °C
In an ecosystem, why can only one species fill an ecological niche?
Answer:
Explanation:es porque las especies con nichos idénticos tienen las mismas necesidades, lo que significa que competirían exactamente por los mismos recursos.
In the following reaction, which are the products?
Mg + 2HCl —> H2 + MgCl2
If you could, please explain as well.
Answer: H2 + MgCl2
Explanation: As they are on the right side of the equation/ are the products being made as a result of the reaction, they are the products.
please answer in details. what class of carbon is coal
Why would cooking equipment be responsible for more total fires but smoking smoking responsible for more fire deaths?
Answer:
For the last few decades fires started by any type of smoking material has been the number one leading cause for household fire fatalities. It could just be that people luckily escape in time with cooking equipment fires, and smoking related fires just result in more deaths.
The diagram shows the setup of an experiment. The observations of the experiment are listed in the table below the diagram. A beaker filled three-fourths with a liquid labeled colorless silver nitrate solution is shown. A small strip is shown inside the beaker. The strip is labeled copper strip. The title of the image is Experimental Setup. Experimental Observations Observation Description 1 Copper strip became thinner 2 Gray particles were deposited on the edge of the strip Which of the following is the correct explanation for one of the given observations? (4 points) Observation 2 is a result of nitrate ions moving into the solution. Observation 2 is a result of silver ions moving into the solution. Observation 1 is a result of copper atoms losing two electrons. Observation 1 is a result of silver atoms losing one electron.
Answer:
The answer is Observation 1 is a result of copper atoms losing two electrons.
Explanation:
The electrons result in the color change of the copper strip, causing the gray particles to join onto the metal.
Answer:
C
Explanation:
Observation 1 is a result of the copper atoms losing two electrons. It came out as the right answer.
A 500ml bottle contains 2.50 moles of gas. What is the new volume when the number of miles is increased 5.00 moles?
Answer:
The new volume is 1,000ml
Explanation:
Mathematically, we know that the number of moles per ml(volume) should be constant irrespective of the increase.
Initially, we have a volume of 500 ml and number of moles of 2.5 moles
The ratio of the number of moles to the volume is 2.5/500 = 0.005 mole/ml
Now, this is expected to remain the same even if we have an increment.
let’s call the new volume x
0.005 mol/ml = 5 moles/x ml
x = 5/0.005 = 1,000 ml
1. Look at yourself in the front of the spoon (the side where the food sits). What do you see?
The you see the image
Answer:
If you look at yourself in the front of the spoon, you see that the mirror forms an inverted real image.
Explanation:
The word 'concave' means to bend inwards.
A curved mirror is a mirror that has a curved reflecting surface.
The front side of the spoon is just like a concave mirror. If you look at yourself in the front of the spoon, you see that the mirror forms an inverted real image.
Concave mirrors produce real inverted image of an object only if it is placed further away from the mirror than the focal point.
Answer:
It shows me upside down like a ghost. OoooOooh
Explanation:
Boo
50 points - I need this really soon! plz help
The pictured compound has which bond?
A.) C = C and C −C
B.) C = C and C −H
C.) C −Cand C −H
D.) C −C, C −H, and C −O
Answer:
C.
Explanation:
Butane (C4H10) has 3 C-C bonds in the carbon chain and 10 C-H bonds
Butane ([tex]C_4H_10[/tex]) has 3 C-C bonds in the carbon chain and 10 C-H bonds
What is alkane?Alkanes are saturated hydrocarbons. This means that their carbon atoms are joined to each other by single bonds.
Based on the diagram, butane is considered to be an alkane. It not only contains single covalent bonds, but also has carbon and hydrogen atoms present in its structure.
When comparing both structures to one another, isobutane is a branched chain, while butane is a linear chain.
Learn more about alkane here:
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Difference between rapid combustion and spontaneous combustion.
Answer: The difference between rapid combustion and spontaneous combustion...
Explanation:
Rapid combustion is a form of combustion, otherwise known as a fire, in which large amounts of heat and light energy are released, which often results in a flame.Whereas spontaneous combustion is the ignition of organic matter (e.g. hay or coal) without apparent cause, typically through heat generated internally by rapid oxidation.
I NEED HELP PLEASE, THANKS SO MUCH! :)
Solids, liquids and gases are the three most commonly accepted phases of matter. Explain the properties of each phase, including their relative energy.
Answer:
Here's what I get
Explanation:
The molecules of a substance attract each other.
They are also in constant motion.
Their kinetic energy increases with the temperature.
1. Solids
If the temperature is low enough, the molecules will have little kinetic energy.
They will not be able to escape the attractions of their neighbours, so they will be fixed in place in a crystalline array.
All they can do is vibrate about their position in the array.
The substance will be a solid.
2. Liquids
If the temperature is higher, the molecules will have enough kinetic energy to slide past each other, but not enough to escape the attractions of nearby molecules.
The substance will be a liquid.
3. Gases
If the temperature is high enough, the molecules will have enough kinetic energy to escape from the surface and fly off into space.
The molecules will on average so far apart that they won't feel the attractions of others.
When they do collide, they will have energy to bounce off each other rather than stick together.
The substance will be a gas.
What is the chemical name of the covalent compound P4O9? A. tetraphosphorus nonaoxygen B. tetraphosphate nonoxygen C. tetraphosphide nonaoxide D. tetraphosphorus nonoxides.
Answer: The chemical name of the covalent compound [tex]P_4O_9[/tex] is, tetraphosphorous nonaoxide.
Explanation:
A covalent compound is a compound where the sharing of electrons takes place between elements where both the elements are non-metals.
The naming of covalent compound is given by:
1. The less electronegative element is written first.
2. The more electronegative element is written second. Then a suffix is added with it. The suffix added is '-ide'.
3. If atoms of an element is greater than 1, then prefixes are added which are 'mono' for 1 atom, 'di' for 2 atoms, 'tri' for 3 atoms and so on.
Hence, the correct name for the compound [tex]P_4O_9[/tex] which is a covalent compound is, tetraphosphorous nonaoxide.
WILL MARK BRAINLIEST IF GOOD EXPLANATION...
Ethyl acetate is a sweet-smelling solvent used in varnishes and fingernail polish remover. It is produced industrially by heating acetic acid and ethanol
together in the presence of sulfuric acid, which is added to speed up the
reaction. The ethyl acetate is distilled off as it is formed. The equation for the
process is as follows.
CH3COOH + CH3CH2OH --> CH3COOCH2CH3 + H2O
Determine the percentage yield in the following cases:
a. 68.3 g of ethyl acetate should be produced but only 43.9 g is recovered.
b. 0.0419 mol of ethyl acetate is produced but 0.0722 mol is expected. (Hint:
Percentage yield can also be calculated by dividing the actual yield in moles
by the theoretical yield in moles.)
c. 4.29 mol of ethanol is reacted with excess acetic acid, but only 2.98 mol of
ethyl acetate is produced.
d. A mixture of 0.58 mol ethanol and 0.82 mol acetic acid is reacted and 0.46
mol ethyl acetate is produced. (Hint: What is the limiting reactant?)
Answer:
a) 64.27%
b) 58%
c) ethanol is the limiting reactant
d) ethanol is the limiting reactant
Explanation:
We have to note that the expected yield is the theoretical yield while the actual mass or amount of product formed is the actual yield.
a) theoretical yield=68.3g
Actual yield= 43.9 g
Percentage yield= 43.9/68.3 ×100
Percentage yield= 64.27%
b) theoretical yield= 0.0722 moles
Actual yield = 0.0419
Percentage yield= 0.0419/0.0722 × 100
Percentage yield= 58%
c) note that the limiting reactant yields the least number of moles of product
Ethanol will be the limiting reactant since it is not present in excess.
d) from the reaction equation;
1 mole of acetic acid produces 1 mole of ethyl acetate
0.58 moles of ethanol produces 0.58 moles of ethyl acetate
1 mole of acetic acid yields 1 mole of ethyl acetate
Hence 0.82 moles of acetic acid yields 0.82 moles of ethyl acetate
Hence ethanol is the limiting reactant.
which of these methods could are used to separate an insoluble solid and soluble solid
Answer:
To separate an insoluble solid from a soluble solid: Mixing the mixture with water, filtering out the insoluble solid, and then evaporating the water to isolate the soluble solid.
Explanation:
Which of the following statements are true? Significant figures in a measurement are all measured digits, and one estimated digit None of the above Significant figures communicate the level of precision in measurements Significant figures are an indicator of the certainty in measurements
Answer: Significant figures in a measurement are all measured digits, and one estimated digit
Significant figures communicate the level of precision in measurements Significant figures are an indicator of the certainty in measurements.
Explanation:
Significant figures : The figures in a number which express the value or the magnitude of a quantity to a specific degree of accuracy or precision is known as significant digits.
The significant figures of a measured quantity are defined as all the digits known with certainty and the first uncertain or estimated digit.
Rules for significant figures:
1. Digits from 1 to 9 are always significant and have infinite number of significant figures.
2. All non-zero numbers are always significant.
3. All zero’s between integers are always significant.
4. All zero’s preceding the first integers are never significant.
5. All zero’s after the decimal point are always significant.
The true statements are
Significant figures in measurement are all measured digits, and one estimated digit
Significant figures communicate the level of precision in measurements Significant figures are an indicator of the certainty in measurements.
The following information should be considered:
The figures in a number that express the value or the magnitude of a quantity is known as significant digits.The significant figures of a measured quantity refers to all the digits known with certainty.Learn more: https://brainly.com/question/1979431?referrer=searchResults
20 points!! Please help me! Will mark Brainliest!! complete the following word equations:) also write the balanced equation, full ionic equation, and net ionic equation. Also include the states:)
a) zinc nitrate + calcium sulphide—>
b) potassium + calcium chloride—>
Calculate the Molarity of a 0.23 mole solution of sucrose, C 12 H 22 O 11 that is dissolved in 5 liters of water.
Answer:
0.046 M
Explanation:
Molarity = mol solute/ L solution = 0.23 mol/ 5 L = 0.046 mol/L = 0.046 M
let's consider the effectiveness of two antacids to illustrate how chemical calculations can be important in daily life. Baking soda NaHCO3, is often used as an antacid. It neutralizes excess hydrochloric acid sereted by stomach. The balanced equation for the reaction is NaHCO3(s)+HCl(aq)=H20(l)+CO2(g). Milk of magnesia, which is an aqueous suspension of magnesium hydroxide, Mg(OH)2(s)+2HCl(aq)=2H20(l)+MgCl2(aq), Which anatacid can consume the most stomach acid, 1.00g of NaHCO3,or 1.00g of Mg (OH)2?
Answer:
Milk of Magnesia would consume the most stomach acid at almost 3 times the amount as baking soda.
Explanation:
Baking Soda = NaHCO3(s)+HCl(aq)=H20(l)+CO2(g)
NaHCO3 Molar mass of 84.007 g/mol
0.012 Moles of NaHCO3 and since an equal ratio of HCl is required
we therefore neutralize 0.012 Moles of HCl
Milk of magnesia = Mg(OH)2(s)+2HCl(aq)=2H20(l)+MgCl2(aq)
Mg(OH)2(s) Molar mass: 58.3197 g/mol
0.017 Moles of Mg(OH)2 and the ratio is 2:1, so 2 moles for each 1 mole of Mg(OH)2, so we need 0.034 Moles of HCl
What is the definition of a scientific theory
A) A method of learning that emphasizes reason as the way to understand the world.
B) A brief statement that summarizes past observations and predicts future ones.
C) A model that explains the underlying reasons for observations and laws.
D) The equivalent of a scientific opinion which others may disagree with.
E) None of these.
Answer:
The correct answer to the following question will be Option C.
Explanation:
The theory seems to be the context within which findings are explained as well as possible predictions are made. This theoretical perspective discusses the factors behind the results as well as the laws.Theories have been used in scientific knowledge to give wide interpretations to accommodate observed facts in case the root reason is still yet to be found as well as characterized.So that Option C will be the right answer.
The electron dot diagram for a neutral atom of chlorine (atomic number 17) is shown below.
Which of the following symbols represents a chlorine ion with a stable arrangement of eight valence electrons?
A. 35Cl1-
B. 35Cl2-
C. 35Cl1+
D. 35Cl
Answer:
A. 35Cl1-
Explanation:
Chlorine needs 1 more electron to have full octet thus will take 1 electron and possess a -1 charge.
Can someone please help me with this question
Answer:
the second one I think...
Answer:
The answer is the first one.
Acceleration is the change of velocity
Velocity is another term for speed with direction.
explain why an indicator is used in titration
Answer:
Titrations. Because a noticeable pH change occurs near the equivalence point of acid-base titrations, an indicator can be used to signal the end of a titration. When selecting an indicator for acid-base titrations, choose an indicator whose pH range falls within the pH change of the reaction.
Hope it helped!!
The density was of a solution of sulfuric acid is 1.285g/cm3 and it is 38.08% (by weight) acid. How many millimeters of the acid solution do you need to supply 125 grams of sulfuric acid?
Answer:
255.5cm³
Explanation:
A solution that is 38.08 % by weight has 38.08g of sulfuric acid per 100g of total solution. Thus, mass of solution you need to obtain 125g is:
125g H₂SO₄ × (100g solution / 38.08g H₂SO₄) = 328.3g of solution
As density of the solution is 1.285g / cm³, the volume of 328.3g is:
328.3g × (1cm³ / 1.285g) = 255.5cm³
