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3 years ago

How long do it take for copper to form

Chemistry

2 answers:

IRINA_888 [86]3 years ago

8 0

Copper doesn't really "form" it is an element

Hope this helps
~Jordan~

kondor19780726 [428]3 years ago

6 0

Copper is an element. So is can't form, but it takes certain types of copper tens of thousands of years depending on where the magma was cooled.

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If the molar mass of the compound in problem 3 is 73.8 grams/mole? what is the molecular formula ?

umka21 [38]

The molecular formula would be Li2CO3

7 0

3 years ago

2. From each of the following pairs of atoms, pick the atom that has

Zina [86]

Answer:

a) Na

c) Na

b) Sr

d) Ca

Explanation:

As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases because it is very difficult to remove the electron from atom and more energy is required.

As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.

As the size of atom increases the ionization energy from top to bottom also decreases because it becomes easier to remove the electron because of less nuclear attraction and as more electrons are added the outer electrons becomes more shielded and away from nucleus.

7 0

3 years ago

A lead mass is heated and placed in a foam cup calorimeter containing 40.0 mL of water at 17.0°C. The water reaches a temperatur

lbvjy [14]

Answer: 502 Joules

Explanation:

To calculate the mass of water, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of water = 1 g/mL

Volume of water = 40.0 mL

Putting values in above equation, we get:

$1g/mL=\frac{\text{Mass of water}}{40.0mL}\\\\\text{Mass of water}=(1g/mL\times 40.0mL)=40.0g$

When metal is dipped in water, the amount of heat released by lead will be equal to the amount of heat absorbed by water.

$Heat_{\text{absorbed}}=Heat_{\text{released}}$

The equation used to calculate heat released or absorbed follows:

$q=m\times c\times \Delta T$

q = heat absorbed by water

$m$ = mass of water = 40.0 g

$T_{final}$ = final temperature of water = 20.0°C

$T_{initial$ = initial temperature of water = 17.0°C

$c$ = specific heat of water= 4.186 J/g°C

Putting values in equation 1, we get:

$q=40.0\times 4.186\times (20.0-17.0)]$

$q=502J$

Hence, the joules of heat were re-leased by the lead is 502

5 0

3 years ago

when 32.4 g of water vapor condenses, how much heat is given off? The heat of vaporization for water is 40.67 kj/mol

egoroff_w [7]

When a water vapor condenses, heat is being released from the process. This heat is called latent heat of vaporization since the phase change happens without any change in the temperature. This value is constant per mole of a substance as a function of pressure and temperature. For this problem, we are given the heat of vaporization at a certain T and P. We use this value to calculate the total heat released from the process. We calculate as follows:

Total heat released: 32.4 g ( 1 mol / 18.02 g ) (40.67 kJ / mol) = 73.12 kJ

Therefore, 73.12 kJ of heat is released from the condensation of 32.4 g of water vapor.

3 0

3 years ago

A series of six solutions was prepared at the given concentrations. Sample A B C D E F Concentration (mM) 50 100 150 200 300 400

ioda

Answer:

300 mM

Explanation:

In order to solve this problem we need to calculate the line of best fit for those experimental values. The absorbance values go in the Y-axis while the concentration goes in the X-axis. We can calculate the linear fit using Microsoft Excel using the LINEST function (alternatively you can write the Y data in one column and X data in another one, then use that data to create a dispersion graph and finally add the line of best fit and its formula).

The formula for the line of best fit for this set of data is:

y = 0.005 * x

So now we calculate the value of x when y is 1.50:

1.50 = 0.005 * x

x = 300 mM

7 0

3 years ago