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Montano1993 [528]
3 years ago
10

A collection of coins contains 15 pennies, 14 dimes and 6 quarters. What is the percentage of pennies in the collection?

Chemistry
1 answer:
pychu [463]3 years ago
8 0

Answer:

42.9%

Explanation:

the total number of coins is 15+14+6 = 35

so to find the % of pennies, divide the number of pennies by the total number of coins and times it all by 100

15/35 x 100 = 42.9%

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NaCl is ___ formula of common salt
MrMuchimi

Answer:

None of them, D

Explanation:

The actual answer is chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions.

5 0
3 years ago
Read 2 more answers
Compare and contrast reflecting and refracting telescopes. *
Alinara [238K]
A refracting telescope uses convex lenses to gather a large amount of light and focus it onto a small area while a reflecting telescope the mirror instead of an objective lens they are also similar because like the lenses in a refracting telescope the mirror in a reflecting telescope focuses a large amount of light onto a small area.
7 0
3 years ago
A sample of gas contains 0.1500 mol of HCl(g) and 7.500×10-2 mol of Br2(g) and occupies a volume of 9.63 L. The following reacti
Furkat [3]

Answer:

9.63 L.

Explanation:

Hello,

In this case, the undergoing chemical reaction is:

2HCl(g) + Br_2(g)\rightarrow 2HBr(g) + Cl_2(g)

So the consumed amounts of hydrochloric acid and bromine are the same to the beginning based on:

n_{Br_2}^{consumed}=0.1500molHCl*\frac{1molBr_2}{2molHCl}=0.075molBr_2

In such a way, the yielded moles of hydrobromic acid and chlorine are:

n_{HBr}=0.1500molHCl*\frac{2molHBr}{2molHCl}=0.1500molHBr \\n_{Cl_2}=0.1500molHCl*\frac{1molCl_2}{2molHCl}=0.075molCl_2

Thus, the volume of the sample, after the reaction is the same as no change in the total moles is evidenced, that is 9.63L.

Best regards.

7 0
3 years ago
If the energy difference between two electronic states is 214.68 kJ / mol , calculate the frequency of light emitted when an ele
atroni [7]

{\qquad\qquad\huge\underline{{\sf Answer}}}

Here we go ~

Energy difference btween the two electronic states can be expressed as :

{ \qquad \sf  \dashrightarrow \: \Delta E = h\nu}

[ h = planks constant,{\: \nu }= frequency ]

\qquad \sf  \dashrightarrow \:214.68 = 39.79 \times 10 {}^{ - 14}  \times  \nu

\qquad \sf  \dashrightarrow \: \nu =  \cfrac{214.68}{39.79 \times 10 {}^{ - 4} }

\qquad \sf  \dashrightarrow \: \nu =  \cfrac{214.68}{39.79 }  \times 10 {}^{14}

\qquad \sf  \dashrightarrow \: \nu  \approx  5.395 \times10 {}^{14}  \:\:hertz

5 0
1 year ago
Determine the volume, in liters, of 3.2 mol of CO2 gas at STP.
Allushta [10]

Answer:

71.7 L

Explanation:

Using the ideal gas equation;

PV = nRT

Where;

P = pressure (atm)

V = volume (L)

n = number of moles (mol)

R = gas law constant (0.0821 Latm/Kmol)

T = temperature (K)

According to the information provided in this question;

P = 1 atm (STP)

V = ?

n = 3.2mol

T = 273K (STP)

Using PV = nRT

V = nRT/P

V = 3.2 × 0.0821 × 273/1

V = 71.7 L

6 0
3 years ago
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