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ASHA 777 [7]
3 years ago
11

Is Helium a compound,element, or.mixture

Chemistry
1 answer:
dusya [7]3 years ago
5 0

Answer:

element

Explanation:

we know that helium is a pure substance although helium atoms are sometimes mixed with their isotopes it is still the same element. since there is no other element combined with helium this makes it an element.

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Q1. Calculate the amount of copper produced in 1.0 hour when aqueous CuBr2 solution was electrolyzed by using a current of 4.50
OLga [1]

Answer:

\boxed{\text{Q1. 3.6 g; Q2. 0.2 A}}

Explanation:

Q1. Mass of Cu

(a) Write the equation for the half-reaction.

Cu²⁺ + 2e⁻ ⟶ Cu

The number of electrons transferred (z) is 2 mol per mole of Cu.

(b) Calculate the number of coulombs

q  = It  

\text{t} = \text{1.0 h} \times \dfrac{\text{3600 s}}{\text{1 h}} = \text{3600 s}\\\\q = \text{3 C/s} \times \text{ 3600 s} = \textbf{10 800 C}

(c) Mass of Cu

We can summarize Faraday's laws of electrolysis as

\begin{array}{rcl}m &=& \dfrac{qM}{zF}\\\\& = &\dfrac{10 800 \times 63.55}{2 \times 96 485}\\\\& = & \textbf{3.6 g}\\\end{array}\\\text{The mass of Cu produced is $\boxed{\textbf{3.6 g}}$}

Note: The answer can have only two significant figures because that is all you gave for the time.

Q2. Current used

(a) Write the equation for the half-reaction.

Ag⁺ + e⁻ ⟶ Ag

The number of electrons transferred (z) is 1 mol per mole of Ag.  

(a) Calculate q

\begin{array}{rcl}m &=& \dfrac{qM}{zF}\\\\2.00& = &\dfrac{q \times 107.87}{1 \times 96 485}\\\\q &=& \dfrac{2.00 \times 96485}{107.87}\\\\& = & \textbf{1789 C}\\\end{array}

(b) Calculate the current

t = 3 h = 3 × 3600 s = 10 800 s

\begin{array}{rcl}q&=& It\\1789 & = & I \times 10800\\I & = & \dfrac{1789}{10800}\\\\& = & \textbf{0.2 A}\\\end{array}\\\text{The current used was $\large \boxed{\textbf{0.2 A}}$}

Note: The answer can have only one significant figure because that is all you gave for the time.

4 0
3 years ago
What is the mass of the missing reactant in the following reactions, given that the reaction goes to completion? Do not include
N76 [4]
1) <span> 2.7 g water + 6,6 g carbon dioxide </span>→<span> 9.3 g carbonic acid.
According to </span><span>principle of mass conservation mass of reactants and products are the same after chemical reactio. 2,7 g + 6,6 g = 9,3 g.
2) </span><span>32.0 g sodium hydroxide + 16.0 g hydrofluoric acid --> 14,4 g water + 33.6 g sodium fluoride.
m(water) = 32 g + 16 g - 33,6 g.
3) </span><span>0.60 g calcium carbonate + 0.48 g sodium hydroxide --> 0,63 g sodium carbonate + 0.45 g calcium.
m(sodium carbonate) = 0,6 g + 0,48 g - 0,45 g.
4) </span><span>0.53 g sodium hydroxide + 0.37 g carbon dioxide --> 0,9 g sodium hydrogen carbonate.
m(sodium hydrogen carbonate) = 0,53 g + 0,37 g = 0,9 g.</span>
6 0
3 years ago
Teeth and long bones are good indicators of age in children; ribs and joints are better for adults.
attashe74 [19]

Answer:

True

Explanation:

7 0
2 years ago
Read 2 more answers
Electrons orbit the nucleus in specified energy
pashok25 [27]

Answer:

because the electron is a negatively charge and have high energy

5 0
3 years ago
Describe 2 similarities of metals and nonmetals
Gelneren [198K]

Answer:

Maybe they both have valence electrons and can be used in chemical reactions. I could be wrong, I don't have any exact answers.

Explanation:

5 0
3 years ago
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