Answer:
21.614 grams are found in [tex]6.5 \times 10^{22}[/tex] molecules of caffeine.
Explanation:
The chemical formula for caffeine is [tex]C_{8}H_{10}N_{4}O_{2}[/tex], the molar weight of caffeine is:
[tex]M = 8\cdot \left(12.011\,\frac{g}{mol} \right) + 16\cdot \left(1.008\,\frac{g}{mol} \right)+4\cdot \left(14.007\,\frac{g}{mol} \right)+2\cdot \left(15.999\,\frac{g}{mol} \right)[/tex]
[tex]M = 200.242\,\frac{g}{mol}[/tex]
According to Avogadro's Law, a mol of caffeine contains [tex]6.022\times 10^{23}[/tex] molecules. The number of grams contained in [tex]6.5 \times 10^{22}[/tex] molecules is determined by simple rule of three:
[tex]x = \frac{6.5\times 10^{22}\,molecules}{6.022\times 10^{23}\,molecules} \times 200.242\,g[/tex]
[tex]x = 21.614\,g[/tex]
21.614 grams are found in [tex]6.5 \times 10^{22}[/tex] molecules of caffeine.
A 150 g sample of brass at 90.0 degrees Celsius is placed in a calorimeter cup that contains 230 g of water at 20.0 degrees Celsius. Disregard the absorption of heat by the cup and calculate the final temperature of the brass and water. Specific heat of water = 4.18 J/gC, specific heat of brass=0.380 J/gC.
Answer:
for brass
mass m1 =150g
t1=90°c
specific heat of brass s1=0.380 J/gC.
for water
t2=20°c
mass m2=230g
Specific heat of water s2= 4.18 J/gC,
Explanation:
we have
Q1=Q2
m1s1{t-t1)=m2s2(t2-t)
150×0.380(t-90)=230×4.18(20-t)
57t-5130=961.4×20-961.4t
57t +961.4t=19228+5130
1018.4t=24358
t=24358/1018.4=23.91=24°c is final temperature
An atom of the element chromium has an atomic number of 24 and a mass number of 52. How many electrons are in an uncharged atom of chromium?
0
24
28
52
Answer:
24
Explanation:
In an uncharged atom, the number of protons is always equal to the number of electrons. For example, carbon atoms include six protons and six electrons, so carbon's atomic number is 6.
Similarly, since an atom of chromium contains 24 protons, it also contains the same amount of electrons, which is 24.
Answer:
24 is your answer
Explanation:
Energy used for metabolism comes primarily from which biomolecules a) Polysaccharides only b) Lipid only c) Lipid and Carbohydrates D) amino acids
Answer:
C) Lipids and Carbohydrates
Explanation:
Lipids, or fats, are stored long-term for energy when an organism cannot find carbohydrates (specifically glucose), which are used as short-term energy.
What happens when the pressure of a gas is decreased?
A. The number of molecules increases.
B. The diffusion rate increases.
C. The temperature increases.
D. The volume increases.
Answer:
The combined gas law states that the pressure of a gas is inversely related to the volume and directly related to the temperature. If temperature is held constant, the equation is reduced to Boyle's law. Therefore, if you decrease the pressure of a fixed amount of gas, its volume will increase.
Explanation:
Answer:
D. The volume increases.
Explanation:
100%
1.a)concentrated sulphuric acid reacts with ethanol to produce ethene
(i) state the conditions for the reaction
.......................................................................
write the equation of the leads to formation of ethene In (a) (i) above.
.....................................................................................
state the property of sulphuric acid shown in reaction (a)(ii)
...................................................................................
Answer: a) Temperature of [tex]170^0C[/tex]
b) [tex]C_2H_5OH\stackrel{conc H_2SO_4, 170^0C}\rightarrow C_2H_4+H_2O[/tex]
c) dehydrating agent
Explanation:
Ethanol is heated with an excess of concentrated sulfuric acid at a temperature of 170°C to produce ethene.
The balanced chemical reaction is:
[tex]C_2H_5OH\stackrel{conc H_2SO_4, 170^0C}\rightarrow C_2H_4+H_2O[/tex]
Here concentrated sulfuric acid removes a water molecule from ethanol and thus acts as a dehydrating agent.
Answer the question using the equation: HCl(aq)+H2O(l)→H+(aq)+Cl-(aq)+H2O(l)→H3O+(aq)+Cl-(aq) Which product is a Lewis base?
Answer:
Cl-
Explanation:
The equation of the reaction is;
H+(aq)+Cl-(aq)+H2O(l)→H3O+(aq)+Cl-(aq)
Lewis base refers to substances that can donate a lone pair of electrons(e.g OH^-, Cl^- etc) or a pair of nonbonding electrons.(eg NH3, H20 etc). A Lewis base is therefore an electron-pair donor. They are easily recognized because they often have lone pairs or are negatively charged species.
If we look at the products, Cl- is a Lewis base because it is a lone pair donor. We see this more clearly because the specie is negatively charged.
Answer:
Cl
Explanation:
Calculate the mass (in g) of solute needed to prepare a solution with the given concentration and volume.
Sea water has a concentration of approximately 0.60 M sodium chloride. How much
sodium chloride is dissolved in 1.00 L of solution?
Coke has a concentration of 0.342 M. What mass of sugar (in g) is dissolved in a 2-L
bottle of coke?
What volume of concentrated nitric acid (15.8 M) is needed to prepare 4.0 L of a 2.0 M solution?
What volume of 9.0 M copper (II) sulfate stock solution is needed to prepare 3.0 L of a 5.0 M
solution?
Answer:
1. 35g NaCl.
2. 234g sugar.
3. 0.506L of concentrated nitric acid are needed.
4. 1.67L of 9.0M copper (II) sulfate are needed
Explanation:
Molarity is defined as the ratio between moles of solute and the volume of the solution.
1. 1.00L * (0.60mol / L) = 0.60 moles NaCl are dissolved
To convert moles to mass we must use its molar mass:
0.60mol NaCl * (58.44g/mol) =
35g NaCl
2. 2L * (0.342mol / L) = 0.684 moles Sugar = moles sucrose
0.684 mol * (342.30g / mol) = 234g sugar
3. 4L of a 2.0M are:
4L * (2.0mol/L) = 8moles
8mol * (1L / 15.8mol) = 0.506L of concentrated nitric acid are needed
4. 3.0L * (5.0 mol / L) = 15.0 moles copper (II) sulfate.
15.0mol * (1L / 9.0mol) = 1.67L of 9.0M copper (II) sulfate are needed
Helppp 88.0 grams of Boron, how many atoms of Boron (B) are present?
Answer:
There are no atoms becuase atoms are not in elements.
Explanation:
with 24.1 moles of P4O10 how many moles of H3PO4 could be made
Why does Play-Doh taste salty?
Pls my science teacher wants an answer so pls answer ASAP i need an explaination
Answer:
It's made of salt
Explanation:
The recipe has salt as an ingredient
Answer:
playdoh is literally made of salt. thats why it tastes salty
Explanation:
help meh......please...
Answer:
The third one
Explanation:
Nickel-62 has the highest binding energy per nucleon of any isotope for any element. Isotopes heavier than 62Ni cannot be formed by nuclear fusion without losing energy.
what is 20+9-10+67=?
Answer:
86
Explanation:
20 plus 9 equals 29 minus 10 equals 19 plus 67 equals 86
Answer:
86
Explanation:
20+9=29
29-10=19
19+67=86
what are the roles of the mucous select two options PLEASE HELP
Answer:
The answer is A and C
Which of the following do/does not change with the change in temperature?
i. Mole fraction.
ii. Molality.
Select one:
a. only i
b. Only ii
c. Both i & ii
d. Neither of them
(I did D and it was incorrect)
Answer:
c. Both i & ii
Explanation:
Moles do not change with temperature hence Mole fraction does not depends of temperature.
Molality is number of moles of solutes per kilogram of solvent. It has no relationship with temperature.
This means both of them do not change wit the change in temperature.
Correct option;
c. Both i & ii
5. If all the particles in a material are made up of
several smaller particles, and every larger particle
is identical, is the material a pure substance or
not? Explain your reasoning.
Answer:
No. Because a pure substance, no matter if an element, compound, it can only contain one kind of particle .
Explanation:
Explain how steam causes burns by describing the transfer of heat.
Answer:
It will be : (in simple terms)
Condensation of hot steam or hot vapor on the cooler skin releases the water's latent heat of vaporization, rapidly raising the temperature of the skin which will result in steam burns.
Hope it helped
All the best!!
Magnesium bromide is prepared in a laboratory using the reaction below. Typically, the magnesium bromide is recoveted as a solid by heating way the remaining water
Mg(s) + 2 HB-(aq) - MgBrac) + H200)
If 0.940 mole of HBr in solution is added to 16.5 grams of Mgo in a beaker and then is heated until dry, what are the expected contents of the beaker?
12 G of carbon react with 16 G of oxygen how much carbon monoxide is formed
Answer:
28 g CO
Explanation:
First convert grams to moles.
1 mole C = 12.011 g (I'm just going to round to 12 for the sake of this problem)
12 g C • [tex]\frac{1 mol C}{12 g C}[/tex] = 1 mol C
1 mol O = 15.996 g (I'm just going to round to 16)
16 g O • [tex]\frac{1 mol O}{16 g O}[/tex] = 1 mol O
So the unbalanced equation is:
[tex]C + O_{2}[/tex] -> [tex]CO[/tex] (the oxygen has a 2 subscript because it is part of HONClBrIF meaning when not in a compound these elements appear in pairs - called diatomic elements)
The balanced equation is:
[tex]2 C + O_2[/tex] -> [tex]2 CO[/tex]
However, carbon is the limiting reactant in this equation and two moles cannot react because only 12 g (1 mole) are present. Therefore, use the equation
[tex]C + \frac{1}{2} O_2[/tex] -> [tex]CO[/tex].
1 mole of CO is formed, therefore 12 g + 16 g = 28 g CO.
How many grams is 40.48 moles of cobalt?
Answer:
2385.49 grams of cobalt.
Explanation:
1. Convert 40.48 moles of Co (cobalt) into grams (mass):
The molar mass of cobalt is 58.933195 g/mol.
[tex]40.48 mol Co = \frac{58.93 g/mol}{1 mol Co} = 2385.49 g[/tex]
Our bodies use nitrogen
Question 2 options:
directly from the air
after bacteria make N into ammonia molecules
from the plants and other animals we eat
all of the above
it's the 1 and 3 I think it's that hopefully it's right
How does an increase in temperature affect the equilibrium concentration of the underlined substance and K for each of the following reactions?
(c) SO2(g) S(s) + O2(g) DH° = 297 kJ
Explanation:
Due to the positive value of the change in temperature, this is an endothermic reaction.
Since the forward reaction is endothermic, increasing the temperature increases the equilibrium constant (k).
In an equilibrium system, the position of the equilibrium will move in a way to annul the change made to the system. An increase in temperature for an endothermic reaction would favour the reaction, leading to increase in amount of products and decrease in amount of reactants.
If a cell were compared to a school, which part of the school would represent the cell's nucleus?
ОА the classroom walls because they give the structure to the school
B
the cafeteria cooks because they make food for the entire school
С
the principal because he or she controls all the activity in the school
D
the fence because it controls what enters and exits the school
Answer:
C-The principal because he or she controls all the activity in the school
How many grams of Ag are produced if I start the reaction with 5.5 mol Cu?
Equation given:
Cu + 2AgNO3 -> 2Ag + Cu(NO3)2
Answer:
9.34 g Ag
Explanation:
What would be the theoretical yield in grams of carbon dioxide in the reaction shown below if 30 g of C6H12O6 were reacted with an excess of oxygen? C6H12O6 + O2 -> CO2 + H2O
Answer: Thus 44 g of [tex]CO_2[/tex] will be produced if 30 g of [tex]C_6H_{12}O_6[/tex] were reacted with an excess of oxygen
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} C_6H_{12}O_6 =\frac{30g}{180g/mol}=0.17moles[/tex]
The balanced chemical equation is:
[tex]C_6H_{12}O_6 +6O_2(g)\rightarrow 6CO_2+6H_2O(g)[/tex]
As [tex]C_6H_{12}O_6[/tex] is the limiting reagent as it limits the formation of product and [tex]O_2[/tex] is the excess reagent.
According to stoichiometry :
1 mole of [tex]C_6H_{12}O_6[/tex] produce = 6 moles of [tex]CO_2[/tex]
Thus 0.17 moles of [tex]C_6H_{12}O_6[/tex] will produce=[tex]\frac{6}{1}\times 0.17=1.0mole[/tex] of [tex]CO_2[/tex]
Mass of [tex]CO_2=moles\times {\text {Molar mass}}=1.0moles\times 44g/mol=44g[/tex]
Thus 44 g of [tex]CO_2[/tex] will be produced if 30 g of [tex]C_6H_{12}O_6[/tex] were reacted with an excess of oxygen.
What element is on period 5 group/family 11
Answer:
47
Ag
Silver
107.87
Explanation:
What volume (in L) of water vapor will be
produced from the reaction of 4.95 L of ethane
(C2He)?
2C2H6(g) + 702(9) — 4CO2(g) + 6H2O(g)
Answer:
14.85L of water are produced
Explanation:
Based on Avigadro's law, the volume is directly proportional to the moles of a gas.
Based on the equation:
2C₂H₆(g) + 7O₂(g) → 4CO₂(g) + 6H₂O(g)
2 moles of ethane produce 6 moles of H₂O.
Using Avogadro's law: 2L of ethane produce 6L of H₂O.
The addition of 4.95L of ethane are:
4.95L ethane * (6L H₂O / 2L C₂H₆) =
14.85L of water are producedWhich is Not part of hydrogen's line-emission spectrum?
Answer: Aufbau series.
Explanation:
"Show a general equation for polymerisation"
Answer:
Polymerisation is the chemical process of monomers joining together to form polymers, often it takes many thousands of monomers to make a single polymer.
Explanation:
Summarize how you would go about calculating the grams of product given the grams of reactant you start with.
What is a reactant?
A- Solid particles that have been separated from a solution
B- A substance that has the ability to be dissolved by a solvent
C- A mixture in which a solid and a liquid or two liquids are mixed occurs
D- The substance present before a chemical reaction occurs
Answer:
it is D
Explanation:
because it is a substance that participants in a chemical reaction.