Answer:
[tex]\boxed {\boxed {\sf A. \ 0.365 \ g\ He}}[/tex]
Explanation:
1. Convert Atoms to Moles
We must use Avogadro's Number: 6.022*10²³. This is the number of particles (atoms, molecules, ions, etc.) in 1 mole of a substance. In this case, the particles are atoms of helium. We can create a ratio.
[tex]\frac {6.022*10^{23} \ atoms \ He}{1 \ mol \ He}[/tex]
Multiply by the given number of helium atoms.
[tex]5.50 *10^{22} \ atoms \ He *\frac {6.022*10^{23} \ atoms \ He}{1 \ mol \ He}[/tex]
Flip the fraction so the atoms of helium cancel.
[tex]5.50 *10^{22} \ atoms \ He *\frac {1 \ mol \ He}{6.022*10^{23} \ atoms \ He}[/tex]
[tex]5.50 *10^{22} *\frac {1 \ mol \ He}{6.022*10^{23} }[/tex]
[tex]\frac {5.50 *10^{22} \ mol \ He}{6.022*10^{23} }= 0.09133178346 \ mol \ He[/tex]
2. Convert Moles to Grams
We must use the molar mass, which is found on the Periodic Table.
Helium (He): 4.00 g/molUse this as a ratio.
[tex]\frac { 4.00 \ g \ He }{ 1 \ mol \ He}[/tex]
Multiply by the number of moles we calculated. The moles will then cancel.
[tex]0.09133178346 \ mol \ He *\frac { 4.00 \ g \ He }{ 1 \ mol \ He}[/tex]
[tex]0.09133178346*\frac { 4.00 \ g \ He }{ 1 }[/tex]
[tex]0.3653271338 \ g\ He[/tex]
3. Round
The original measurement has 3 significant figures (5, 5, and 0). Our answer must have the same. For the number we calculated, it is thousandth place. The 3 in the ten thousandth place tells us to leave the 5.
[tex]0.365 \ g\ He[/tex]
The mass is 0.365 grams of helium so choice A is correct.
Which of the following is a human activity that can cause climate change?
A) burning fossil fuels
B) removing greenhouse gases
C) using alternative energy sources
D) increasing particulates from volcanoes
Answer:
D) increasing particulates from volcanoes
Explanation:
Answer:
A) burning fossil fuels
Explanation:
B would help or slow down climate change, C would as well and D is something natural and not human-caused.
good luck, i hope this helps :)
3. What is the meaning of coordination number?
Answer:
Explanation:
Its simple
This is the number of atoms, ions, or molecules that a central atom or ion holds as its nearest neighbours in a complex or coordination compound or in a crystal.
for example: Sodium chloride (NaCl) or table salt is an ionic compound. It means that each cation will have exactly one anion associated with it, which means the cation Na+ and the anion Cl− have the same number of coordinates.
It may be really confusing at first
I recommend you go online and watch tutorial videos on the topic
A spider has several eyes.
What is the main function of these organs?
I’ll give y’all 100 points
Answer:
it is d
Explanation:
Answer: d
Explanation: i think that answer
How many grams will be needed to make a 1.00 Liter solution of 0.500M
sodium chloride?
Mass of NaCl = 29.25 g
Further explanationGiven
A 1.00 Liter solution of 0.500 M Sodium chloride
Required
Mass of NaCl
Solution
Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution
[tex]\large{\boxed {\bold {M ~ = ~ \frac {n} {V}}}[/tex]
Input the value :
n = M x V
n = 0.5 x 1
n = 0.5 mol
Mass NaCl :
= mol x MW
= 0.5 x 58.5
= 29.25 g
Which set of molecule representations correctly match.
Answer:
D
Explanation:
THERE ARE 3 HYDROGEN ATOMS AND 1 NITROGEN SUPPORTING THE FORMULA OF AMMONIA NH3 AND TOTAL ATOMS IS ALSO 4.
Determine the number of protons, neutrons, and electrons:
Answer:
Hey Mia! This is what I put for my answer.
Explanation:
I hope this helps and have a good day :)
define alkylenes and alkanes
Answer:
Alkylenes: any of the series of unsaturated hydrocarbons containing a triple bond, including acetylene.
alkanes: Alkanes are organic compounds that consist entirely of single-bonded carbon and hydrogen atoms and lack any other functional groups. Alkanes have the general formula CnH2n+2 and can be subdivided into the following three groups: the linear straight-chain alkanes, branched alkanes, and cycloalkanes.
Explanation:
What is the name of the covalent compound PCl5
Answer:
Phosphorus pentachloride
Explanation: P is Phosphorus, Cl is Chlorine. Penta is latin for 5.
The name of the covalent compound PCl₅ is phosphorous pentachloride as it has five chlorine atoms.
What is an atom?
An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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what is the formula for the polyatomic ion and name the following compound
Sn(NO2)2
The chemical formula for the polyatomic ion is NO₂⁻ and name of the following compound is tin (II) nitrite.
Chemical formula is a way of representing the number of atoms present in a compound or molecule.It is written with the help of symbols of elements. It also makes use of brackets and subscripts.
Subscripts are used to denote number of atoms of each element and brackets indicate presence of group of atoms. Chemical formula does not contain words. Chemical formula in the simplest form is called empirical formula.
There are four types of chemical formula:
1)empirical formula
2) structural formula
3)condensed formula
4)molecular formula
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How many atoms are in 2.5mol of sodium
Answer:
1024 sodium atoms.
How much volume would a sample of galena have it its mass was 300 grams?
Answer:
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What are three forms of the element carbon?
Answer:
There are at least eight forms of carbon: amorphous, graphite, diamond, fullerenes, aggregated diamond nanorods, carbon nanofoam, glassy carbon, and linear acetylenic carbon.
Explanation:
Please HELP!!! Automotive airbags inflate when sodium azide decomposes explosively to its constituent elements. How many grams of sodium azide are required to produce 24.4 L of nitrogen gas at standard temperature and pressure? 2NaN3 --> 2Na + 3N2
47.2 g of sodium azide
106.2 g of sodium azide
1.63 g of sodium azide
0.726 g of sodium azide
Answer: 47.2 g of sodium azide
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
To calculate the moles, we use the equation:
[tex]\text{Number of moles of nitrogen}=\frac{\text{Given volume}}{\text {Molar volume}}=\frac{24.4L}{22.4L}=1.09moles[/tex]
The balanced chemical reaction is:
[tex]2NaN_3\rightarrow 2Na+3N_2[/tex]
According to stoichiometry :
3 moles of [tex]N_2[/tex] are produced by = 2 moles of [tex]NaN_3[/tex]
Thus 1.09 moles of [tex]N_2[/tex] are produced by =[tex]\frac{2}{3}\times 1.09=0.73moles[/tex] of [tex]NaN_3[/tex]
Mass of [tex]NaN_3=moles\times {\text {Molar mass}}=0.73moles\times 65g/mol=47.2g[/tex]
Thus 47.2 g of sodium azide are required to produce 24.4 L of nitrogen gas at standard temperature and pressure
How many moles of H2 would be formed from 2.26 mol of HCI?
Mg + _HCI → _MgCl2 + H2
Answer:
2.6 moles of HCl will produce moles of H2 = [tex]1.3[/tex]
Explanation:
Mass of HCl is 36.458 g/mol
Mass of Hydrogen is 1.00794 g/mol
The balanced equation here is
Mg + 2_HCI → _MgCl2 + H2'
2 moles of HCl produces one mole of H2
One mole of HCl will produce moles of H2 = [tex]\frac{1}{2}[/tex]
2.6 moles of HCl will produce moles of H2 = [tex]\frac{1}{2} * 2.6 = 1.3[/tex]
you have a sample of 23.8 g of C2H6. how many moles of C2H6 are in the sample?
Be sure to show your work and each step is writing out clearly.
Answer:
0.791 moles are present in the sample
Explanation:
To convert mass to moles of a substance you must find the molar mass of the susbtance.
The molar mass of C₂H₆ is:
2C = 12.01g/mol*2 = 24.02g/mol
6H = 1.01g/mol*6 = 6.06g/mol
Molar mass = 24.02g/mol + 6.06g/mol = 30.08g/mol is the molar mass of C₂H₆
And the moles of 23.8g of this substance are:
23.8g * (1mol / 30.08g) =
0.791 moles are present in the sampleA rock climbing group reached the top of Mount Everest in the Himalayan mountains. Mount Everest is about 29,000 feet above sea level and formed by the interaction of two tectonic plates. The group leader was surprised to find fossilized marine organisms on top of the mountain. Which of the following describes the geologic history of Mount Everest?
answer choices:
A: Two tectonic plates had different densities which caused the denser plate containing fossilized marine organisms to rise above the surface and form the Himalayan mountains.
B: Two tectonic plates had different densities which caused one plate to subduct into the ocean and the other one to rise causing marine organisms to fossilize on top of Mount Everest.
C: Two tectonic plates had the same density which caused one plate to subduct into a transform boundary that fossilized marine organisms before the Himalayan mountains were formed and uplifted.
D: Two tectonic plates had the same density and a collision of the plates pushed the advancing plate that contained fossilized marine organisms upward forming the Himalayan mountains and Mount Everest.
Answer:
Two tectonic plates had the same density and a collision of the plates pushed the advancing plate that contained fossilized marine organisms upward forming the Himalayan mountains and Mount Everest.
In an ecosystem comprising of the Himalayan region,following describes the geologic history of Mount Everest that two tectonic plates had the same density and a collision of the plates pushed the advancing plate that contained fossilized marine organisms upward forming the Himalayan mountains and Mount Everest.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the ecosystem through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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Sugar
O2
CO2
H2O
What is the name of this energy pathway?
thnxx for free point? ?????????
A rock face at the top of a mountain is composed of layers in which seashells are embedded. This type of rock is
Answer:
Sedimentary rock.
Explanation:
When limestone form as ocean water evaporates and leaves calcium carbonate behind, they are then deposited in the seabed. Thus, the type of rock that can be formed this way is a sedimentary rock.
The texture of organic land-derived sedimentary rocks is fragmental or clastic. Sediments come from living organisms such as plants and animals to form organic sedimentary rocks.
Some examples of inorganic land-derived sedimentary rocks are conglomerate, brescia and sandstone.
In this scenario, a rock face at the top of a mountain is composed of layers in which seashells are embedded. This type of rock is a sedimentary rock.
Can a chemical reaction be both exothermic and endothermic? Explain.
Explanation:
reaction cannot be both endothermic and exothermic at the same time.
How many formula units of CaO are in 32.7 g of CaO?
A) 0.58 formula units
B) 1.96 x 1025 formula units
C) 56.08 formula units
D) 3.51 x 1023 formula units
Answer:
D) 3.51x10²³ formula units
Explanation:
To know this, we need to calculate the molecular mass of CaO. To do that, let's use the atomic mass of each element of this compound.
Ca: 40.08 g/mol; O: 16 g/mol
With these given AM, let's calculate the molar mass of CaO:
Mm CaO = 40.08 + 16 = 56.08 g/mol
Now that we have the MM of CaO, it's time to determine the moles of CaO:
moles = mass / MM
moles = 32.7 / 56.08 = 0.5831 moles
Finally to get the formula units, we need to use the Avogadro's number which is 6.02x10²³. According to this number, 1 mole of any substance has this number of atoms, molecules or formula units. So, if we have 0.5831 moles, then the formula units will be:
FU = 0.5831 * 6.02x10²³
FU = 3.51x10²³ formula unitsHope this helps
Where and how does respiration take place
Answer:
Glucose and oxygen react together in cells to produce carbon dioxide and water and releases energy. The reaction is called aerobic respiration because oxygen from the air is needed for it to work. Energy is released in the reaction. The mitochondria , found in the cell cytoplasm, are where most respiration happens.
1.572x108 Troy oz of silver were used in the us in 1980 how many kilograms is this
Answer: 4873200 kg
Explanation:
Given mass: [tex]1.572\times 10^8[/tex] troy oz
Conversion factor : [tex]1troyoz=0.031kg[/tex]
Thus if 1 troy oz weighs in kg = 0.031 kg
[tex]1.572\times 10^8[/tex] troy oz will weigh in kg =[tex]\frac{0.031}{1}\times 1.572\times 10^8=0.04873\times 10^8kg[/tex]
Thus there are [tex]0.04873\times 10^8kg[/tex] in [tex]1.572\times 10^8[/tex] troy oz of silver used.
name two objects which are hard to touch
Answer:
Name of two hard objects is Brick and Wood.
fire and mercury
i think i am not sure
but pls brainlist
Based upon the percent yield you calculated, what is one source of error, and the resulting of that error in your experiment.
Select the option corresponding to the following choices
a. When decanting, some solid was lost, resulting in less copper recovered and a lower % yield
b. When decanting, some solid was lost, resulting in more copper recovered and a higher % yield
c. When drying over the steam bath, did not let the sample dry completely, resulting in a higher mass of copper recovered, and a higher % yield.
d. When drying over the steam bath, did not let the sample dry completely, resulting in a lower mass of copper recovered, and a lower % yield.
Answer:
The answer is "Choice a".
Explanation:
In the given question, through the basis of their determined percentage yield, a smaller copper increase in value and less copper has been lost during decanting, but now this mistake in your experiment was the cause of confusion, and the wrong choice can be defined as follows:
In point b, it is wrong because A few other solids were not lost during decanting, resulting in a higher recovery of copper as well as a boost in the percentage yieldIn point c, it is wrong because whenever the vapor bath was dried, the specimen did run dry totally, which did result in such a heavier density of copper and a larger percentage of the yield.In point d, it is wrong because whenever the vapor bath was dried, the sample was fully dried, which also resulted in much less adhesive weight and a much less percentage of the yield.Use the following equation:
2 CO (g) + O2 (g) = 2 CO2 (g)
How many moles of CO and O2 are required to produce 10 moles of CO2?
A) 10 moles of CO and 5 moles O2
B) 5 moles of CO and 10 moles of O2
C) 2 moles of CO and 1 mole O2
D) 2 moles of CO and 2 moles CO2
Answer:
A) 10 moles of CO and 5 moles O2
is this right someone please help asap photo attached above
The number of moles in 75.0 liters of F2 at STP
Draw the organic product(s) formed when CH3CH2CH2OH is treated with each reagent. a. H2SO4 e. SOCl2, pyridine i. [1] TsCl, pyridine; [2] NaSH b. NaH f. PBr3 j. POCl3, pyridine c. HCl ZnCl2 g. TsCl, pyridine d. HBr h. [1] NaH; [2] CH3CH2Br
Answer:
See answer below
Explanation:
In this case, we are treating an alcohol with different reagents to give different products. In the picture below you have the draw of each product, and here, the explanation.
a) H₂SO₄: In this case, it will promote an E1 reaction forming an alkene as product.
b) NaH: In this case, it will promote an acid base reaction, and the final product will be an alcoxide.
c) HCl/ZnCl₂: In this case, primary alcohols reacts with this reactive to form an alkyl halide.
d) HBr: Another reaction forming an alkyl halide with bromine in this case.
e) SOCl₂: Similar to c), it will form an alkyl chloride.
f) PBr₃: Similar to d, forming an alkyl bromide.
g) TsCl: Here it will be a sustitution reaction, where tosilate replaces the OH
h) NaH/CH₃CH₂Br: In this case it will form an alcoxide and then, a larger alkyl.
i) TsCl/NaSH: First it will form a tosilate and then, the SH group. A sustitution reaction.
j) POCl₃: A sustitution reaction forming an alkyl chloride.
See picture below for drawings.
Hope this helps
g You have decided to add ethidium bromide directly to your agarose solution before you pour you gel. You have a stock solution of 6 mg/ml and you want a final concentration of 0.5 g/ml in your 50 ml agarose solution. Calculate how much of the stock solution you will need to make add to the agarose solution to give you a final concentration of 0.5 g/ml.
Answer:
4.17mL of the stock solution of ethidium bromide must be added in the 50mL agarose solution
Explanation:
You want to dilute the ethidium bromide from 6mg/mL to 0.5mg/mL, that is:
6mg/mL / 0.5mg/mL = 12 times the stock solution must be diluted.
As the final volume of the solution is 50mL, you must add:
50mL / 12 =
4.17mL of the stock solution of ethidium bromide must be added in the 50mL agarose solution
What happened to Mendeleev's mother after he was accepted into St. Petersburg University?
Answer:
his mother died i think
Explanation:
Although he was not accepted, his mother was determined to give her son a first-class education and they walked to St. Petersburg. Dmitri was accepted into the Institute of Pedagogy on a full scholarship. That same year his mother died and at the age of sixteen, Dmitri was orphaned.