Answer:
14 hrs.
Explanation:
From the question given above, the following data were obtained:
Time (t) = 42 hrs
Original amount (N₀) = 4.32 g
Amount remaining (N) = 0.54 g
Half-life (t½) =…?
Next, we shall determine number of half-lives required for 4.32 g of the isotope to decay to 0.54 g. This can be obtained as follow:
Original amount (N₀) = 4.32 g
Amount remaining (N) = 0.54 g
Number of half-lives (n) =?
N = 1/2ⁿ × N₀
0.54 = 1/2ⁿ × 4.32
Cross multiply
0.54 × 2ⁿ = 4.32
Divide both side by 0.54
2ⁿ = 4.32 / 0.54
2ⁿ = 8
Express 8 in index form with 2 as the base
2ⁿ = 2³
n = 3
Thus, it took 3 half lives for 4.32 g of the isotope to decay to 0.54 g.
Finally, we shall determine the half-life of the isotope. This can be obtained as follow:
Time (t) = 42 h
Number of half-lives (n) = 3
Half-life (t½) =
n × t½ = t
3 × t½ = 42
Divide both side by 3
t½ = 42 / 3
t½ = 14 hrs
Thus, the half-life of the isotope is 14 hrs
When NH3(aq) is added to Cu2 (aq), a precipitate initially forms. Its formula is:
a. Cu(NH)3
b. Cu(NO3)2
c. Cu(OH)2
d. Cu(NH3)22
e. CuO
When NH₃(aq) is added to Cu₂(aq), a precipitate initially forms. Its formula is Cu(NH₃)². The correct option is d.
What is a chemical formula?A chemical formula is a representation of chemical elements and chemical compounds. The chemical letters are used to write the chemical formula. The charges if present is written by charges symbols like plus, minus.
The chemical reaction is
NH₃(aq) + Cu₂(aq) = Cu(NH₃)²
This is called a chemical reaction, which contains reactant on the left side and products on the right side. The precipitate that is formed is copper ammonia whole twice.
Precipitation is the solid crystals' substance that is come out at the surface of the liquid. It is collected in solid form, and it is called a precipitate.
Thus, the correct option is d. Cu(NH₃)².
To learn more about chemical formulas, refer to the link:
https://brainly.com/question/15138610
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Question 3 (1 point)
Consider the following unbalanced chemical equation representing the combustion of methane, yielding carbon dioxide and water.
CH4 + O2 --> CO2 + H20
If you had burned 800 g of methane, how many moles of Carbon dioxide would be produced?
A)122.22
B)8
C)2200
D)100
E)670
F)750
G)50
Answer:
Im pretty sure its B
Explanation:
Answer:
G) 50 mol
Explanation:
Given data:
Mass of methane = 800 g
Number of moles of CO₂ produced = ?
Solution:
Chemical equation:
CH₄ + 2O₂ → CO₂ + 2H₂O
Number of moles of methane:
Number of moles = mass/molar mass
Number of moles = 800 g/ 16 g/mol
Number of moles = 50 mol
Now we will compare the moles of methane and carbon dioxide.
CH₄ : CO₂
1 : 1
50 : 50
What are the products of the acid-base reaction of sodium carbonate with acetic acid?
Answer:
The mixture quickly foams up with carbon dioxide gas. If enough vinegar is used, all of the baking soda can be made to react and disappear into the vinegar solution. The reaction is: Sodium bicarbonate and acetic acid reacts to carbon dioxide, water and sodium acetate.
Explanation:
hope this helps
A chemist dissolves of pure potassium hydroxide in enough water to make up of solution. Calculate the pH of the solution. (The temperature of the solution is .) Be sure your answer has the correct number of significant digits.
Answer:
12.99
Explanation:
A chemist dissolves 716. mg of pure potassium hydroxide in enough water to make up 130. mL of solution. Calculate the pH of the solution. (The temperature of the solution is 25 °C.) Be sure your answer has the correct number of significant digits.
Step 1: Given data
Mass of KOH: 716. mg (0.716 g)Volume of the solution: 130. mL (0.130 L)Step 2: Calculate the moles corresponding to 0.716 g of KOH
The molar mass of KOH is 56.11 g/mol.
0.716 g × 1 mol/56.11 g = 0.0128 mol
Step 3: Calculate the molar concentration of KOH
[KOH] = 0.0128 mol/0.130 L = 0.0985 M
Step 4: Write the ionization reaction of KOH
KOH(aq) ⇒ K⁺(aq) + OH⁻(aq)
The molar ratio of KOH to OH⁻is 1:1. Then, [OH⁻] = 0.0985 M
Step 5: Calculate the pOH
We will use the following expression.
pOH = -log [OH⁻] = -log 0.0985 = 1.01
Step 6: Calculate the pH
We will use the following expression.
pH + pOH = 14
pH = 14 - pOH = 14 -1.01 = 12.99
Explain the concept of “Happy Atoms” as it relates to why atoms bond together.
Answer:
I think this means that they always compatible so th er e basically friends and they stick together. c: hope I helped
A chemist adds of a M calcium sulfate solution to a reaction flask. Calculate the mass in grams of calcium sulfate the chemist has added to the flask
Answer:
1.23 g
Explanation:
A chemist adds 1.55 L of a 0.00582 M calcium sulfate solution to a reaction flask. Calculate the mass in grams of calcium sulfate the chemist has added to the flask.
Step 1: Given data
Volume of the solution (V): 1.55 LMolar concentration of the solution (C): 0.00582 M (0.00582 mol/L)Step 2: Calculate the moles (n) of calcium sulfate added
We will use the following expression.
n = C × V
n = 0.00582 mol/L × 1.55 L
n = 0.00902 mol
Step 3: Calculate the mass corresponding to 0.00902 moles of calcium sulfate
The molar mass of calcium sulfate is 136.14 g/mol.
0.00902 mol × 136.14 g/mol = 1.23 g
Which describes a difference between cephalopods and gastropods?
Cephalopods have a water vascular system, and gastropods have an open circulatory system.
Cephalopods live only in ocean environments, and gastropods live in a variety of environments.
Cephalopods have a simple nervous system, and gastropods have a complex nervous system.
Cephalopods are the largest group of mollusks, and gastropods are the smallest group of mollusks. CAN SOMEONE PLZZZZ ANWER THIS I WILL GIVE U 15 PIONTS
Answer:
B
Explanation:
I took the test
Answer:
The correct answer is B
Explanation: