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Solnce55 [7]
3 years ago
13

A researcher claims that an ancient scroll originated from greek scholars in about 500 bce. a measure of its carbon-14 decay rat

e gives a value that is 89% of that found in living organisms. how old is the scroll? (the half-life of carbon-14 is 5730 yr.) express the time in years as an integer.
Chemistry
1 answer:
Naddik [55]3 years ago
8 0
The amount of substance present in a certain object with a given half-life in terms of h can be expressed through the equation,

     A(t) = (A(o))(0.5)^(t/h)

where A(t) is the amount of substance after t years and A(o) is the original amount. In this item we are given that A(t)/A(o) is equal to 0.89. Substituting the known values,

     0.89 = (0.5)(t / 5730 years)

The value of t from the equation is 963.34 years.

<em>Answer: 963 years</em>
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Part 1. A chemist reacted 18.0 liters of F2 gas with NaCl in the laboratory to form Cl2 gas and NaF. Use the ideal gas law equat
Alika [10]

Answer:

Part 1

The mass of the NaCl that reacted with F₂ at 290.K and 1.5 atm is approximately 132.6 gams

Part 2

The mass of NaCl that can react with the same volume of gas at STP is approximately 93.77 grams

Explanation:

Part 1

The volume of F₂ gas in the reaction, V = 18.0 liters

The ideal gas equation is P·V = n·R·T

∴ n = P·V/(R·T)

The pressure, P = 1.5 atm

The temperature, T = 290 K

The universal gas constant, R = 0.0820573 L·atm/(mol·K)

∴ n = 1.5×18/(0.0820573 × 290) ≈ 1.134615

The number of moles of F₂ in the reaction n ≈ 1.134615 moles

The chemical reaction is given as follows;

F₂ + 2NaCl → Cl₂ + 2NaF

1 mole of F₂ reacts with 2 moles of NaCl

Therefore;

1.134615 moles of F₂ reacted with 2 × 1.134615 moles ≈ 2.26923 moles of NaCl

1 mole of NaCl = The molar mass of NaCl, MM = 58.44 g/mol

The mass, of 2.26923 moles of NaCl, m = Number of moles × MM

∴ m ≈ 2.26923 moles × 58.44 g/mol ≈ 132.6 grams

The mass of the NaCl ≈ 132.6 gams

Part 2

The volume occupied by 1 mole of all gases at STP = 22.4 l/mole

Therefore, the number of moles of F₂ in 18.0 L of F₂ = 18.0 L/(22.4 L/mole) ≈ 0.804 moles

Therefore;

The number of moles of NaCl, in the reaction n = 2 × The number of moles of F₂ ≈ 2×0.804 moles = 1.608 moles

The number of moles of NaCl, in the reaction n ≈ 1.608 moles

The mass of NaCl in the reaction, m = n × MM

∴ m ≈ 1.608 moles × 58.44 g/mol ≈ 93.97 grams

The mass of NaCl that can react with the same volume of gas at STP ≈ 93.77 grams

8 0
3 years ago
An important reaction that takes place in a blast furnace during the production of iron is the formation of iron metal and CO2 f
ladessa [460]

Answer: Mass of Fe_2O_3 required to form 930 kg of iron is 1328 kg

Explanation:

To calculate the number of moles, we use the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}      .....(1)

For iron:

Given mass of iron = 930 kg = 930000 g  (1kg=1000g)

Molar mass of iron = 56 g/mol

Putting values in equation 1, we get:

\text{Moles of iron}=\frac{930000g}{56g/mol}=16607mol

The chemical equation for the  production of iron  follows:

Fe_2O_3+3CO\rightarrow 2Fe+3CO_2

By Stoichiometry of the reaction:

2 moles of iron are  produced by =  1 mole of Fe_2O_3

So, 16607 moles of iron will be produced by = \frac{1}{2}\times 16607=8303moles of Fe_2O_3

Now, calculating the mass of Fe_2O_3 from equation 1, we get:

Mass of Fe_2O_3 = moles\times {\text {molar mass}}=8303\times 160=1328480g=1328kg

Thus mass of Fe_2O_3 required to form 930 kg of iron is 1328 kg

6 0
3 years ago
Draw the product formed by the reaction of potassium t-butoxide with (1s,2s)-1-bromo-2-methyl-1-phenylbutane (shown below). (dra
VikaD [51]
 <span>You have to use a Newman projection to make sure that the H on C#2 is anti-coplanar with the Br on C#1. (Those are the two things that are going to be eliminated to make the alkene.) 

My Newman projection looks like this when it's in the right configuration: 
Front carbon (C#2) has ethyl group straight up, H down/left, and CH3 down/right 
Back carbon (C#1) has H straight down, Ph up/left, and Br up/right. 

Then when you eliminate the H from C#2 and the Br from C#1, you will have Ph and the ethyl group on the same side of the molecule, and you'll have the remaining H and CH3 on the same side of the molecule. 

This is going to give you (Z)-2-methyl-1-phenyl-1-butene.</span>
3 0
3 years ago
Read 2 more answers
The following molecular equation represents the reaction that occurs when aqueous solutions of silver(I) nitrate and calcium chl
dsp73

Answer:

Ag+(aq) + Cl-(aq) —> AgCl(s)

Explanation:

2AgNO3(aq) + CaCl2(aq) —>2AgCl(s) + Ca(NO3)2(aq)

The balanced net ionic equation for the reaction above can be obtained as follow:

AgNO3(aq) and CaCl2(aq) will dissociate in solution as follow:

AgNO3(aq) —> Ag+(aq) + NO3-(aq)

CaCl2(aq) —> Ca2+(aq) + 2Cl-(aq)

AgNO3(aq) + CaCl2(aq) –>

2Ag+(aq) + 2NO3-(aq) + Ca2+(aq) + 2Cl-(aq) —> 2AgCl(s) + Ca2+(aq) + 2NO3-(aq)

Cancel out the spectator ions i.e Ca2+(aq) and 2NO3- to obtain the net ionic equation.

2Ag+(aq) + 2Cl-(aq) —> 2AgCl(s)

Divide through by 2

Ag+(aq) + Cl-(aq) —> AgCl(s)

The, the net ionic equation is

Ag+(aq) + Cl-(aq) —> AgCl(s)

4 0
3 years ago
When a strontium atom loses two electrons to form an Sr2+ ion, the electrons are lost from the
kherson [118]

Answer:When a strontium atom loses two electrons, it becomes a(n) cation with a charge of 2+. when any neutral atom loses an electron it becomes cation that is positively charged ions and an ion gets the charge according to the number of electrons loses.

you are very welcome but I may be inaccurate.

6 0
3 years ago
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