Platinum-189<br> What is the atomic number

A student places a beaker on a hot plate. To the beaker, he adds a clear liquid and a white powder. The mixture instantly begins

Elenna [48]

True, because if it wasn't a chemical reaction it would have proceeded to stay the same. but it begins to bubble.
sorry if this isn't the best answer I'm trying my best.

7 0

3 years ago

Read 2 more answers

The rate of effusion of an unknown gas was measured and found to be 11.9 mL/min. Under identical conditions, the rate of effusio

iren2701 [21]

Answer : The correct option is, (B) $CO_2$

Solution :

According to the Graham's law, the rate of effusion of gas is inversely proportional to the square root of the molar mass of gas.

$R\propto \sqrt{\frac{1}{M}}$

or,

$(\frac{R_1}{R_2})=\sqrt{\frac{M_2}{M_1}}$ ..........(1)

where,

$R_1$ = rate of effusion of unknown gas = $11.9\text{ mL }min^{-1}$

$R_2$ = rate of effusion of oxygen gas = $14.0\text{ mL }min^{-1}$

$M_1$ = molar mass of unknown gas = ?

$M_2$ = molar mass of oxygen gas = 32 g/mole

Now put all the given values in the above formula 1, we get:

$(\frac{11.9\text{ mL }min^{-1}}{14.0\text{ mL }min^{-1}})=\sqrt{\frac{32g/mole}{M_1}}$

$M_1=44.2g/mole$

The unknown gas could be carbon dioxide $(CO_2)$ that has approximately 44 g/mole of molar mass.

Thus, the unknown gas could be carbon dioxide $(CO_2)$

5 0

3 years ago

If you have 1 proton and 2 electrons, what is the overall charge of the ion?

marysya [2.9K]

The overall charge will be negative 1

4 0

3 years ago

Please help<br><br><br> How many moles are there in 7.57 x 10^30 molecules of CO2?

Oxana [17]

Answer:

The answer is

<h2>12,574,750.83 moles</h2>

Explanation:

In order to find the moles of CO2 we use the formula

$n = \frac{N}{L} \\$

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question

N = 7.57 × 10^30 molecules of CO2

We have

$n = \frac{7.57 \times {10}^{30} }{6.02 \times {10}^{23} } \\ = 12574750.83056...$

We have the final answer as

<h3>12,574,750.83 moles</h3>

Hope this helps you

3 0

2 years ago

while doing a lab, a student found the density of a piece of pure aluminum to be 2.85 g/cm^3. the accepted value for the density

vagabundo [1.1K]

Answer:

Percent error = 5.6%

Explanation:

Given data:

Measured value of density by students = 2.85 g/cm³

Accepted density of aluminium = 2.70 g/cm³

Percent error = ?

Solution:

Formula:

Percent error = [ Measured value - accepted value / accepted value ]× 100

Now we will put the values in formula:

Percent error = [ 2.85 g/cm³ - 2.70 g/cm³ / 2.70 g/cm³ ]× 100

Percent error = [0.15/2.70 g/cm³ ] × 100

Percent error = 0.056× 100

Percent error = 5.6%

7 0

3 years ago

Platinum-189 What is the atomic number