Please help!<br>Gravity and magnetism are examples of?

A. How many moles of copper equal 8.00 × 109 copper atoms?

BARSIC [14]

Answer:

Explanation:

a ) one mole = 6.02 x 10²³ atoms

no of moles in given no of atoms

= 8 x 10⁹ / 6.02 x 10²³

= 1.329 x 10⁻¹⁴ moles .

b ) one mole of calcium = 40 gram

102 .5 g calcium

= 102 .5 / 40 moles

= 2.5625 moles

c )

no of moles in 5.04 g lead = 5.04 / 207

= 2.4347 x 10⁻² moles

= 2.4347 x 10⁻²x 6.02 x 10²³ no of atoms of lead

= 14.6568 x 10²¹ no of atoms .

d)

one mole = 6.02 x 10²³ atoms

2.85 mole = 17.157 x 10²³ atoms .

e )

moles of fluorine gas = 1.08 x 10³ / 6.02 x 10²³

= .1794 x 10⁻²⁰ moles

mass in grams = .1794 x 10⁻²⁰ x 38

= 6.8172 x 10⁻²⁰ grams

f )

no of moles in .584 g of benzene = .584 / 78

= 7.487 x 10⁻³ moles

no of molecules = 6.02 x 10²³ x 7.487 x 10⁻³

= 45.07 x 10²⁰ molecules .

g )

moles of atoms = 5.09 x 10⁹ / 6.02 x 10²³

= .8455 x 10⁻¹⁴ moles

mass in gram = .8455 x 10⁻¹⁴ x 1

= .8455 x 10⁻¹⁴ g

h )

.45 moles of Ca₃PO₄ = .45 x 6.02 x 10²³ molecules

= 2.709 x 10²³ molecules of Ca₃PO₄

no of atoms of Ca = 3 x 2.709 x 10²³

= 8.127 x 10²³ atoms of Ca .

7 0

3 years ago

5. Which statement is true about electronegativity?

Anit [1.1K]

Answer:

Electronegativity generally increases from left to right across a period,

Explanation:

The true statement from the given choices is that electronegativity generally increases from left to right across a period.

Electronegativity is the measure of the relative tendency with which an atom of the element attract valence electrons in a chemical bond.

Across a period electronegativity increases from left to right and decreases down the group.

This is due to reduction in metallic properties as we move across the period from left to right.

3 0

2 years ago

A gas sample has volume 3.00 dm3 at 101

gavmur [86]

Answer:

V₂ = 21.3 dm³

Explanation:

Given data:

Initial volume of gas = 3.00 dm³

Initial pressure = 101 Kpa

Final pressure = 14.2 Kpa

Final volume = ?

Solution;

The given problem will be solved through the Boly's law,

"The volume of given amount of gas is inversely proportional to its pressure by keeping the temperature and number of moles constant"

Mathematical expression:

P₁V₁ = P₂V₂

P₁ = Initial pressure

V₁ = initial volume

P₂ = final pressure

V₂ = final volume

Now we will put the values in formula,

P₁V₁ = P₂V₂

101 Kpa × 3.00 dm³ = 14.2 Kpa × V₂

V₂ = 303 Kpa. dm³/ 14.2 Kpa

V₂ = 21.3 dm³

Explanation:

3 0

2 years ago

Water flows from the bottom of a large tank where the pressure is 100 psig through a pipe to a turbine which produces 5.82 hp. T

Marianna [84]

Explanation:

Bernoulli equation for the flow between bottom of the tank and pipe exit point is as follows.

$\frac{p_{1}}{\gamma} + \frac{V^{2}_{1}}{2g} + z_{1}$ = $\frac{p_{2}}{\gamma} + \frac{V^{2}_{2}}{2g} + z_{2} + h_{f} + h_{t}$

$\frac{(100 \times 144)}{62.43} + 0 + h[tex] = [tex]\frac{(50 \times 144)}{(62.43)} + \frac{(70)^{2}}{2(32.2)} + 0 + 40 + 60$

h = $\frac{(50 \times 144)}{(62.43)} + \frac{(70)^{2}}{2(32.2)} + 40 + 60 - \frac{(100 \times 144)}{(62.43)}$

= 60.76 ft

Hence, formula to calculate theoretical power produced by the turbine is as follows.

P = mgh

= $100 \times 60.76$

= 6076 lb.ft/s

= 11.047 hp

Efficiency of the turbine will be as follows.

$\eta_{t}$ = $\frac{P_{actual}}{P_{theoretical}}$ × 100%

= $\frac{5.82}{11.047} \times 100%$

= 52.684%

Thus, we can conclude that the efficiency of the turbine is 52.684%.

4 0

3 years ago

A green rat snake that lives in the grass and a brown rat snake that lives in the desert is a form of what ?

liberstina [14]

A green rat snake that lives in the grass and a brown rat snake that lives in the desert is a form of geographically separated species.

Explanation:

The habitats of the green rat snake and brown rat snake shows that they are geographically separated species.

The two rat snakes are different species because of their distinct habitat and morphology.

When two species get separated by habitat their breeding method changes either by morphology or breeding pattern.

Such species do not produce viable offspring.

Thus a green rat snake and a brown rat snake have very different habitats they are now two different species.

Such species are said to be reproductively isolated species. Two species having genetic divergence undergo natural selection to adapt to the environment.

6 0

3 years ago

Please help!Gravity and magnetism are examples of?​

Please help!Gravity and magnetism are examples of?