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3 years ago

How many H2O molecules are contained in 0.0016 moles of the hydrate Na2B4O7.10H2O?

2 answers:

8 0

Maybe this example could help you to understand this problem.

https://image.slidesharecdn.com/121howmanyatoms-091201144624-phpapp02/95/12-1-how-many-atoms-17-728....

MaRussiya [10]3 years ago

5 0

<span>https://image.slidesharecdn.com/121howmanyatoms-091201144624-phpapp02/95/12-1-how-many-atoms-17-728.... </span>

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An ionized helium atom has a mass of 6.6 × 10-27 kg and a speed of 5.3 × 105 m/s. It moves perpendicular to a 0.78-T magnetic fi

arsen [322]

Explanation:

In a magnetic field, the radius of the charged particle is as follows.

r = $\frac{mv}{qB}$

where, m = mass, v = velocity

q = charge, B = magnetic field

Therefore, q will be calculated as follows.

q = $\frac{mv}{rB}$

= $\frac{6.6 \times 10^{-27} \times 5.3 \times 10^{5}}{0.014 m \times 0.78 T}$

= $\frac{34.98 \times 10^{-22}}{0.01092}$

= $3.2 \times 10^{-19} \times \frac{1.0 e}{1.6 \times 10^{-19}C}$

= +2e

Thus, we can conclude that the charge of the ionized atom is +2e.

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2 years ago

Ammonium nitrate is an ingredient in cold packs used by sports trainers for injured athletes. Calculate the change in temperatur

Ronch [10]

Answer:

See explanation

Explanation:

First, we need to use the correct expression:

Q = m*Cp*ΔT (1)

Q = n*ΔH (2)

These are the 2 expressions to calculate heat or energy.

Now, we want to know the change of temperature of the nitrate in water after being added, so with the innitial data of nitrate, we can calculate heat using the second expression. First, we need to calculate moles with the molecular mass:

n = m/MM

n = 42/80.1 = 0.52 moles

With these moles, we can calculate heat with the ΔH of this reaction:

Q = 0.52 * 25.7 = 13.364 kJ or 13,364 J

However, this heat as is being absorbed, the value would be negative.

Now that we have heat, we can use expression (1) and plug these values to solve for ΔT, but before, we need to know the total mass of the solution (water + nitrate)

m = 250 + 42 = 292 g

now, solving for ΔT:

-13,364 = 292 * 4.18 * ΔT

ΔT = -13,363 / (292 * 4.18)

ΔT = -10.95 °C

3 0

3 years ago

Help plisssssssssss I need helppp

Makovka662 [10]

Answer:

Explanation:

you would have to look more around the page, for example look at some ways that you can right down.