All categories

2 years ago

1. How many atoms are there in 1.7 mol Ca?

Chemistry

2 answers:

ella [17]2 years ago

7 0

answer: 3g. 17kg+3 ÷ 0.25

Dominik [7]2 years ago

5 0

There are $2.55\times10^{23}$ atoms in 1.7 mol Ca

<u>Solution:</u>

Initially we have to convert the given mass of calcium to moles of calcium, using its molar mass (referring to a periodic table, this is 40.08 g/mol

$1.7 \text { g Ca }\left(\frac{1 \text{ mol Ca}}{40.08 \text{ g Ca}}\right)= 0.0424 \text{ mol Ca}$

Using Avogadro's number, $6.022 \times 10^{23} \text{ particles per mol}$ as $1 \text{ mole }=6.022\times 10^{23}$

We can calculate the number of atoms present by $0.0424 \text{ mol Ca}\times\frac{6.022 \times 10^{23}}{1 \text{ mol }}=2.55\times10^{23} \text { atoms Ca }$

You might be interested in

You add 50.0 g of ice initially at ‒20.0 °C to 1.00 x 102 mL warm water at 67.0 °C. When all the ice melts, the water temperatur

xxTIMURxx [149]

Answer:

$T_2=17.8\°C$

Explanation:

Hello,

In this case, we can solve this problem by noticing that the heat lost by the warm water is gained by the ice in order to melt it:

$Q_{water}=-Q_{ice}$

In such a way, the cooling of water corresponds to specific heat and the melting of ice to sensible heat and specific heat also that could be represented as follows:

$m_{water}Cp_{water}(T_2-T_{water})=-m_{ice}\Delta H_{melting,ice}-m_{ice}\Cp_{ice}(T_2-T_{ice})$

Thus, specific heat of water is 4.18 J/g°C, heat of melting is 334 J/g and specific heat of ice is 2.04 J/g°C, thus, we can compute the final temperature as shown below:

$m_{water}Cp_{water}(T_2-T_{water})+m_{ice}Cp_{ice}(T_2-T_{ice})=-m_{ice}\Delta H_{melting,ice}\\\\T_2=\frac{-m_{ice}\Delta H_{melting,ice}+m_{water}Cp_{water}T_{water}+m_{ice}Cp_{ice}T_{ice}}{m_{water}Cp_{water}+m_{ice}Cp_{ice}} \\\\T_2=\frac{-50.0*334+100*4.18*67+50.0*2.04*-20.0}{100*4.18+50.0*2.04} \\\\T_2=17.8\°C$

Best regards.

3 0

2 years ago

jake pushes a heavy box across a carpeted floor.Name three forces that act on the box, and explain how you know these are unbale

Fantom [35]

I actually learned about this stuff about 3 years ago and this is what I can tell you what I remember and hopefully it helps in a way...
[Newton’s law of motion]
There’s unbalanced forces, friction, and balanced forces.
Unbalanced forces is where the object (in this case the box) is moving in one direction because one of the forces is applying more pressure than the other
Friction is where the box would be harder to push but if it’s still an unbalanced force, it will still move in one direction. The surfaces of the ground and or object isn’t smooth. Therefore creating difficulty when moving it.
A Balanced force will not move the object in any direction. This is because there is an equal amount of force being applied to all opposing sides. The net force will always equal 0 when there’s a balanced force!

-HOPE THAT HELPED IN A WAY! <3

6 0

2 years ago

All mixtures can be separated by physical processes. true or false

DaniilM [7]

<span>True. In chemistry, mixtures are two (or more) substances mixed together but not combined chemically. This means there are no chemical bonds that have formed between the substances. As such, they can be separated with physical processes.</span>

7 0

2 years ago

You and your lab partner are asked to determine the density of an aluminum bar. The mass is known accurately to 4 significant fi

zmey [24]

Answer:

Average density for method A = 2.4 g/cm³

Average density for method B = 2.605 g/cm³

Explanation:

In order to calculate the average density for each method, we need to add the data for each method, and then divide the result by the number of measurements (in this case is 4 for both methods):

For Method A:

Σ = 2.2 + 2.3 + 2.7 + 2.4 = 9.6

Average = 9.6/4 = 2.4 g/cm³

For Method B:

Σ = 2.603 + 2.601 + 2.605 + 2.611 = 10.420

Average = 10.420/4 = 2.605 g/cm³

5 0

2 years ago

2. A chemical analysis of a sample provides the following elemental data:

Vadim26 [7]

Answer:

C3 H6 O2

Explanation:

first divide their mass by their respective molar mass, we get:

30.4 moles of C

61.2 moles of H

20.25 moles of O

now divide everyone by the smallest one of them then we get

C= 1.5

H= 3

O= 1

since our answer of C is not near to any whole number so we will multiply all of them by 2

so,

C3 H6 O2 is our answer

3 0

1 year ago