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2 years ago

How many grams (g) are in 0.250 moles of copper?

Chemistry

1 answer:

MissTica2 years ago

5 0

Answer:

15.89grams

Explanation:

The mass of a substance can be calculated from it's mole value by using the formula:

mole = mass/molar mass

According to this question, there are 0.250 moles of copper. Hence, the mass of copper can be calculated as follows:

Molar mass of Cu = 63.55g/mol

0.250 = mass/63.55

mass = 0.250 × 63.55

mass = 15.8875

Mass of Cu in 0.250mol is 15.89grams.

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What are the common parts of a nucleotide?

a_sh-v [17]

1. Phosphate Group,Pentose sugar, and Nitrogen base
2. Not sure
3.These are found in RNA cytosine, guanine, adenine and uracil.

8 0

3 years ago

NItrogen in air reacts at high temperature to form NO2 according to the reaction:

Rina8888 [55]

Answer:

The correct answer is option E.

Explanation:

Structures for the reactants and products are given in an aimage ;

Number of double bonds in oxygen gas molecule = 1

Number of double bonds in nitro dioxide gas molecule = 1

Number of single bond in in nitro dioxide gas molecule = 1

Number of triple bonds in nitrogen gas molecule = 1

$N_2+2O_2\rightarrow 2NO_2,\Delta H=?$

$\Delta H=[2 mol\times \Delta H_{f,NO_2}]-[1 mol\times \Delta H_{f,N_2}-2 mol\times \Delta H_{f,O_2}]$

$\Delta H_{f,NO_2}=33.18 kJ/mol$

$\Delta H_{f,N_2}=0$ (pure element)

$\Delta H_{f,O_2}=0$ (pure element )

$\Delta H=2 mol\times 33.18 kJ/mol=66.36kJ=15.86 kcal$

The enthalpy of the given reaction is 15.86 kcal.

6 0

3 years ago

The element carbon exists in several different forms. Pure carbon can be found in the form of diamonds, coal, and the graphite i

UNO [17]

Answer:

B) All carbon atoms have 6 neutrons.

Explanation:

The false statement from the given choices is that all carbon atoms have 6 neutrons.

There is a phenomenon called isotopy in chemistry.

Isotopy is the existence of two or more atoms of the same element having the same atomic number but different mass numbers due to the differences in the number of neutrons in their various nuclei.

These atoms of elements are called isotopes.
Carbon atoms generally have proton number of 6 which is the same as the atomic number.
As with all atoms, the mass number or atomic mass equals the number of protons and neutrons.

For the isotopes of carbon, their number of neutrons differs.

For example:

The number of neutrons differs in the above isotopes.

Number of neutrons = mass number - atomic number;

¹²₆C , number of neutrons = 12 - 6 = 6

¹³₆C, number of neutrons = 13 - 6 = 7

¹⁴₆C, number of neutrons = 14 - 6 = 8

Therefore, based on the concept of isotopy, all carbon atoms do not have 6 neutrons.

7 0

2 years ago

Why are fixed resistors’ values indicated by color bands rather than printing the numeric value on their exterior?

gladu [14]

Because there are so many different values of numbers, it would be impractical to use 1Ω, 2Ω, 3Ω... etc... Using colored bands helps make reading it a little easier to the trained eye. There are hundreds of thousands, if not tens of millions of different resistors would need to exist to cover every value. So you just use something called "preferred values" with their resistance values posted on them instead.

6 0

3 years ago

A wooden boat discovered just south of the great pyramid in egypt has a carbon-14>carbon-12 ratio that is 72.5% of that found

Kazeer [188]

The half life for C14 is 5730 years.

We assume that Carbon 14/ Carbon 12 ratio was steady for living organisms over time, the problem is actually telling us that
$\frac{Nt}{N0}$ = 0.0725 = $\frac{1}{2}$ ˣ

Take the natural logarithm and In on both sides.
ln(0.725) = ln $\frac{1}{2}$ ˣ
= - 0.3216 = xln ( $\frac{1}{2}$ = -0.6931x.
So x = (-.3216) / (-0.6931) = 0.464
or

t/t₁/₂ = 0.464
So t = 0.464 x t₁/₂ = 0.464 * 5730 yrs = 2660 years.

7 0

2 years ago