The sample of Carbon-14 after 28,575 years=0.001875 mg
Further explanationGeneral formulas used in decay:
[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{T/t\frac{1}{2} }}}[/tex]
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
Carbon-14 has a half-life of 5715 years, so t1/2=5715 years
A sample today contains 0.060 mg of carbon-14, so No=0.06 mg, then :
[tex]\tt Nt=0.06(\dfrac{1}{2})^{28575/5715}\\\\Nt=0.06(\dfrac{1}{2})^5\\\\Nt=0.001875~mg[/tex]
How many atoms are in 39.2 g of calcium?
a) 6.022 x 10^23 aoms
b) 235.2 x 10^23 atoms
c) 5.89 x 10^23 atoms
d) 40.08 x 10^23 atoms
Answer:
5.89× 10²³ atoms of Ca
Explanation:
Given data:
Mass of Ca = 39.2 g
Number of atoms = ?
Solution:
Number of moles of Ca:
Number of moles = mass/molar mass
Number of moles = 39.2 g/40.078 g/mol
Number of moles = 0.978 mol
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
0.978 mol × 6.022 × 10²³ atoms / 1 mol
5.89× 10²³ atoms of Ca
Car battery energy that makes device work
Answer:
No it's not make device work
Explanation:
I think soo
Which of the following is a simple definition of reduction?
A. the loss of electrons
B. the gain of electrons
C. an agent that oxidizes something
D. an agent that reduces something
The answer is B on Edg 2020
Answer:
B. the gain of electrons
Explanation:
An easy way to remember this concept is the pneumonic OIL RIG:
Oxidation is Loss (of electrons)
Reduction is Gain (of electrons)
How many moles of nitrogen gas would be produced if 3.27 moles of copper(II) oxide were reacted with excess ammonia in the following chemical reaction? 2 NH3(g) + 3 CuO (s) – 3 Cu(s) + N2(g) + 3 H2O(g)
Moles of Nitrogen(N₂) gas would be produced : 1.09
Further explanationThe reaction coefficient in a chemical equation shows the mole ratio of the components of the reactants and products
If one mole of the reactant or product is known, then we can determine the moles of the other compounds involved in the reaction
Reaction
2NH₃(g) + 3CuO (s) ⇒ 3Cu(s) + N₂(g) + 3 H₂O(g)
Copper(II) oxide was reacted with excess Ammonia, so CuO as a limiting reactant and moles of the product is based on moles of CuO
moles of CuO = 3.27
From the equation, the mol ratio of CuO : mol N₂ = 3 : 1, so mol N₂ :
[tex]\tt \dfrac{1}{3}\times 3.27=1.09[/tex]
Silver nitrate and magnesium chloride react according to the following equation:
2AgNO3(aq) + MgCl2(aq) — 2AgCl(s) + Mg(NO3)2(aq)
What volume (in ml) of 0.247M MgCl2(aq) is required to react with 63.2 mL of 0.192M AgNO3(aq)?
Answer:
V=24,3mL
Explanation:
1)n(AgNO3)=Cm*V=0.063l*0.192M=0.012
2)n(AgNO3)/2=n(MgCl2) => MgCl2=0.012/2=0.006
3)V(MgCl2)=n/Cm=0.006/0.247=0.0243L=24,3ml