Answer:
17188 years
Explanation:
Given that;
0.693/t1/2 = 2.303/t log (Ao/A)
Where;
t1/2 = half life of carbon -14
t = time taken
Ao = activity of a living sample
A activity of the artifact
0.693/5730 = 2.303/t log (32/4)
1.21 * 10^-4 = 2.303/t * 0.9031
1.21 * 10^-4 = 2.0798/t
t = 2.0798/1.21 * 10^-4
t = 17188 years
why are the Alkali Metals the first row of the periodic table?
Explanation:
All atoms naturally want to have a completely full outermost shell of electrons.Howevee, elements in that first column of the periodic table all have one electron in their outermost shell. ..."since the alkali metals only have one valence electron,they typically achieve this state by giving up that electron.
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An increase in the volume of a substance because of an increase in temperature is called
Answer:
Its called contraction.
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
Select the correct answer.
Which phrase describes a polymer?
A.
a branching structure containing 10 carbon atoms and 22 hydrogen atoms
B.
a crystal containing many sodium ions and many fluoride ions
C.
a long chain of carbon atoms with hydrogen atoms attached to them
D.
a molecule containing six carbon atoms arranged in a ring structure
E.
a single atom of calcium bonded to two atoms of chlorine
C. a long chain of carbon atoms with hydrogen atoms attached to them.
Explanation:
Answer:
C.
a long chain of carbon atoms with hydrogen atoms attached to it
8.The number of protons plus neutrons is represented by the
a.atomic number
b.mass number
c.atomic mass
d.isotope
Answer:
c.atomic mass
Explanation:
The total number of protons plus neutrons is called the atomic mass number for the atom.
What element is on period 5 group/family 11
Answer:
47
Ag
Silver
107.87
Explanation:
Where is the air pressure greater-- at sea level or on a mountaintop? Explain
Answer:
Air pressure is greater at sea level than at the top of a mountain. The amount of air at sea level is greater than that on top of a mountain.
Explanation:
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what is C6H6+O2--> CO2+H2O balanced
Answer:
2C6H6 + 15O2 → 12CO2 + 6H2O
Answer:
2C6H6 + 15O2 --> 12CO2 + 6H2O
Which element has the largest atomic radius?
Be
F
Ga
Ba
Answer:
Ba
Explanation:
The trend for atomic radius is that it increases as you go down and decreases as you go right.
can someone help me convert these please !
NaCl
+
Ba3(PO4)2
Na3PO4
+
BaCl2
1000 grams of sodium chloride is combined with 2000
grams of barium phosphate.
a)What is the limiting reactant?
b) How many grams of excess reactant are left?
Answer:
a) Sodium Chloride is the limiting reactant.
b)285g of Ba3(PO4)2
Explanation:
a) 1000g Nacl x (1mol of Nacl/58.5g) x (2 Mol Na3PO4/6 mol of NaCl)= 5.70
- 2000g Ba3 (PO4)2 X 1 mol of Ba3 (PO4)2/601.9 x 2 mol of Na3PO4/1 mol of Ba3 (PO4)2= 6.65
Hence; NaCl is the limiting Reactant.
b) 1000g Nacl x (1mol of Nacl/58.5g) x 1 mol of Ba3 (PO4)2/ 6 mol of NaCl x601.9g/1 mol= 1715g Ba3(PO4)2 USED.
2000g- 1715g=285g of Ba3(PO4)2 Left.
Sodium chloride is a limiting reagent.
284 grams of barium phosphate (excess reactant) are left.
Explanation:
Given:
[tex]6NaCl+Ba_3(PO_4)_2\rightarrow 2Na_3PO_4+3BaCl_2[/tex]
1000 grams of sodium chloride and 2000 grams of barium phosphate.
To find:
The limiting reactant and mass of excess reactant left.
Solution:
Mass of sodium chloride = 1000 g
Moles of sodium chloride =[tex]\frac{1000 g}{58.44 g/mol}=17.11mol[/tex]
Mass of barium phosphate = 2000 g
Moles of barium phosphate =[tex]\frac{2000 g}{601.93 g/mol}=3.323 mol[/tex]
[tex]6NaCl+Ba_3(PO_4)_2\rightarrow 2Na_3PO_4+3BaCl_2[/tex]
According to reaction, 6 moles of sodium chloride reacts with 1 mole of barium phosphate, then 17.11 moles of sodium chloride will react with:
[tex]=\frac{1}{6}\times 17.11mol=2.852 \text{ mol of }Ba_3(PO_4)_2[/tex]
2.852 moles of barium phosphate reacted with 17.11 moles of sodium chloride.
But according to the question, we have 3.323 moles of barium phosphate which is more than 2.852 moles.
This indicates that barium phosphate is an excessive reagent and sodium chloride is a limiting reagent.
Moles of barium phosphate left unreacted:
[tex]=3.323 mol - 2.852 mol = 0.471 mol[/tex]
Mass of 0.471 moles of barium phosphate:
[tex]=0.471 mol\times 601.93 g/mol=283.51\approx 284 g[/tex]
Sodium chloride is a limiting reagent.
284 grams of barium phosphate (excess reactant) are left.
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How many atoms are in 25.00 g of Li.
Answer:
6.022×1023 atoms
Explanation:
Energy exists in different forms. Which of the following forms of energy best describes the energy stored
in food?
A. electromagnetic energy
B. mechanical energy
C. sound energy
D. chemical energy
Answer:
D. chemical energy
Explanation:
Food contains chemical energy as chemical energy is stored in bonds.
is chex mix an example of a pure substance or mixture?
An illustration of a mixture is Chex Mix. It is made out of a variety of blended ingredients, including Chex cereal, pretzels, almonds, and spices.
A mixture is a grouping of two or more compounds that are physically mixed but are not chemically bound in chemistry. Each component of the combination keeps its unique characteristics and can be physically separated from it using techniques like filtration or distillation. Both homogeneous and heterogeneous mixtures exist. Homogeneous mixtures, like seawater, have a consistent composition throughout, whereas heterogeneous combinations, like oil and water, have separate phases and an unequal distribution. An illustration of a mixture is Chex Mix.
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Round the measurement to 3 significant figures. 13.06
Answer: 13.1
Explanation: just round the .06 to 1 creating three sig figs.
Convert CH4 to C2H6?
Dehydration of alcohol by conc. H2SO4.....?
Answer:
1.
CH4 + Cl2 → CH3-Cl + HCl
2CH3-Cl +2Na → C2H6
2.
CH3-CH2-OH ---(conc. H2SO4)----> CH2=CH2 + H2O
Explanation:
1. Conversion of methane to ethane
Step 1 - Treat methane with chlorine gas presence of ultraviolet light
CH4 + Cl2 → CH3-Cl + HCl
Step 2 - Treat chloromethane formed in step 1 with the sodium metal and dry ether (Wrutz synthesis)
2CH3-Cl +2Na → C2H6
2. On treating ethanol with excess of concentrated sulfuric acid, it converts into ethene
CH3-CH2-OH ---(conc. H2SO4)----> CH2=CH2 + H2O
you were stranded on an island with your little brother or little sister and the only thing you have saved in your bag are a plastic envelope with two sheets of bond paper and a roll of sewing thread while waiting for somebody to rescue you how can you use that you materials to cheer up your brother
Answer:
well with that you can make a water maker that might make you brother happy because it will keep him alive
Explanation:
Answer:
you could sew a doll for him
or you could punch him in the face and tell him to cheer up
Explanation:
What is the mass of 2.542 × 1026 atoms of F?
Answer:
7.98 × 10^3grams.
Explanation:
To find the mass of fluorine in the number of atoms provided, we first divide the number of atoms by Avagadros number (6.02 × 10^23atoms) to get the number of moles in the fluorine atom. That is;
number of moles (n) = number of atoms (nA) ÷ 6.02 × 10^23 atoms
n = 2.542 × 10^26 ÷ 6.02 × 10^23
n = 0.42 × 10^ (26-23)
n = 0.42 × 10^3
n = 4.2 × 10^2moles
Using mole = mass ÷ molar mass
Molar/atomic mass of fluorine (F) = 19g/mol
mass = molar mass × mole
Mass (g) = 19 × 4.2 × 10^2
Mass = 79.8 × 10^2
Mass = 7.98 × 10^3grams.
Solid to Gas
As a change is state takes place, heat _______ and temperature _______.
A. Increases, stay the same
B. Stay the same, changes
C. Increases, increases
Answer:
c. c. c c c c c cçcc. ccccccccc
Explanation:
ccc cc
When solid converts to gas then heat is required to break the intermolecular forces of attraction between the particles. In this process heat increase but temperature remains the same. So option A is correct option.
What is phase transition?Phase transition is a process in which transition takes place from one state to another of a medium on changing temperature or pressure. Phase transition is a physical process as there is no breaking of old bond and forming of new bonds takes place.
During phase transition temperature remain constant as the extra heat that is given to the system that goes into breaking of intermolecular forces of attraction between the particles. So overall temperature remains same but heat keeps on increasing. Hence option A is correct.
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Newton's Third Law of Motion states that objects exert equal forces on each other in opposite directions.
Which of the following examples best describe Newton's Third Law of Motion?
Answer: a truck crashes into a car
Explanation:
The truck drives in a wrong motion which makes the reaction of it crashing.
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.
Construct an ICE table to calculate the equilibrium concentration of S2− in a solution containing 0.04 mol of Fe(NO3)2. The Ksp of FeS is 8.0 x 10−19. Complete the table by typing in the correct answer, represented by the orange letters in the ICE table. (When typing a number that is between 0 and 1, insert a 0 before the decimal, and type values to two decimal places.)
Answer: a: 0.04
b: 0
c: x
d: x
e: x
f: 0.04
Explanation:
Classify the waves as longitudinal or transverse.
Answer:
the bell is longitudinal
the secound one is transverse
third is longitudinal
the fourth is transverse
Explanation:
i got it right on my mastery test
The combustion of a sample of butane, C4H10 (lighter fluid), produced 2.46 grams of water.
2 C4H10 + 13O2 -------> 8CO2 + 10H2O
(a) How many moles of water formed?
(b) How many moles of butane burned?
(c) How many grams of butane burned?
(d) How much oxygen was used up in moles?
(e) How much oxygen was used up in grams?
a. 0.137
b. 0.0274
c. 1.5892 g
d. 0.1781
e. 5.6992 g
Further explanationGiven
Reaction
2 C4H10 + 13O2 -------> 8CO2 + 10H2O
2.46 g of water
Required
moles and mass
Solution
a. moles of water :
2.46 g : 18 g/mol = 0.137
b. moles of butane :
= 2/10 x mol water
= 2/10 x 0.137
= 0.0274
c. mass of butane :
= 0.0274 x 58 g/mol
= 1.5892 g
d. moles of oxygen :
= 13/2 x mol butane
= 13/2 x 0.0274
= 0.1781
e. mass of oxygen :
= 0.1781 x 32 g/mol
= 5.6992 g
0.137moles of water is formed, 0.0274 moles or 1.5892 g of butane burned and 0.1781 moles or 5.6992 g of O₂ is used.
What is combustion reaction?Those reaction in which fuel is oxidized by the oxygen molecules and produce carbon dioxide and water molecule.
Given chemical reaction is:
2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O
Given mass of water = 2.46 grams
Moles will be calculated as:
n = W/M, where
W = given mass
M = molar mass
(a) Moles of water formed is calculated as:
Moles of water n = 2.46g / 18 g/mol = 0.137moles
(b) From the stoichiometry of the reaction, it is clear that:
10 moles of water = produced by 2 moles of butane
0.137 moles of water = produced by 2/10×0.137=0.0274 moles of butane
(c) Weight of butane is calculated by using moles:
W = 0.0274 × 58 g/mol = 1.5892 g
(d) From the stoichiometry of the reaction, it is clear that:
2 moles of butane = react with 13 moles of O₂
0.027 moles of butane = react with 13/2×0.027=0.1781 moles of O₂
(e) Mass of oxygen is calculated as:
W = 0.1781 x 32 g/mol = 5.6992 g
Hence, (a) 0.137moles, (b) 0.0274 moles, (c) 1.5892 g, (d) 0.1781 moles and (e) 5.6992 g.
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why do non-metal aroms form covalent bonds e.g. H2O
Answer:
Covalent bonds usually occur between nonmetals. For example, in water (H2O) each hydrogen (H) and oxygen (O) share a pair of electrons to make a molecule of two hydrogen atoms single bonded to a single oxygen atom. ... Covalent compounds tend to be soft, and have relatively low melting and boiling points.
How does the number of protons compare to the number of
electrons in a canton
Answer: The number of protons in cation is more than the number of electrons
Explanation:
cations are positive ions that means that they lose electrons to be stable nd have electron configuration (atomic number ) equivalent to the preceding noble gas
as : sodium 11 , it loses on electron to be stable and its electron configuration is equivalent to neon 10
so ,the number of protons in cation is more than the number of electrons
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Use the half reaction method to balance the following reaction in acid:
I2 + Na2S2O3 -> Na2S2O4 + NaI
Answer:
I2 + 2S2O3^2- --------> S4O6^2- + 2I^-
Explanation:
The correct equation is;
2Na2S2O3 + I2 → Na2S4O6 + 2NaI
Oxidation half equation;
2S2O3^2- --------> S4O6^2- + 2e-
Reduction half equation;
I2 + 2e ----------> 2I^-
Overall balanced redox reaction equation;
I2 + 2S2O3^2- --------> S4O6^2- + 2I^-
Which of the following metals (M) will form an ionic compound with nitrogen with the general formula M3N2?
a
lithium (Li)
b
sodium (Na)
c
aluminum (Al)
d
beryllium (Be)
Beryllium (Be) will form an ionic compound with nitrogen with the general formula M[tex]_3[/tex]N[tex]_2[/tex]. Therefore, the correct option is option D.
What is metal?Metal refers to any of a class of substances that have excellent electrical and thermal conductivity, malleability, flexibility, or light reflection. Metals account for over 75% of any and all chemical elements currently known.
Aluminum, iron, salt, potassium, and magnesium are the most abundant elements in the Earth's crust. Most metals can be found in ores, while some, such as copper, gold, platinum, even silver, are frequently found in their free state because they do cannot easily react with other elements. Beryllium (Be) will form an ionic compound with nitrogen with the general formula M[tex]_3[/tex]N[tex]_2[/tex].
Therefore, the correct option is option D.
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In a fractionating column, what process is caused by heating?
Answer:
During the fractional distillation of crude oil: heated crude oil enters a tall fractionating column , which is hot at the bottom and gets cooler towards the top. vapours from the oil rise through the column. vapours condense when they become cool enough.
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The fractionating column's crystal clear glass beads provide such a vast surface area for heated vapors to cool and condensed continuously.
The fractionating column is inserted into the mouth of the distillation flask, which contains the saturated solution to be separated.
Heated crude oil is pumped into a tall fractionating column that is heated at the bottom and cools as it rises.
The oil fumes ascend through the column. When vapors cool down sufficiently, they condense. Various heights are used to lead liquids out of the columns.
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To what category do carnivores, herbivores, and omnivores belong? O A. producer O B. consumer O C. decomposer O D. composer
Answer:
B for sure
Explanation:
Because they all consume