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3 years ago

Which matter exists in the gaseous state at room temperature?

Chemistry

2 answers:

Tpy6a [65]3 years ago

3 0

Helium i would think so

padilas [110]3 years ago

3 0

The answer is B. Helium. If you look at the periodic table, Helium is a noble gas, and all noble gases are in the gas phase at room temperature.
Hope this helped ^-^

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How many elements are in 2CaCO3 and C8H10N402

Ilia_Sergeevich [38]

Answer:

In 2CaCO3 there is 3 elements.

In C8H10N402 there is 3 elements.

3 0

3 years ago

6) (a) Calculate the absorbance of the solution if its concentration is 0.0278 M and its molar extinction coefficient is 35.9 L/

Anvisha [2.4K]

Answer:

6) (a) 0.499; (b) 31.7 %

7) 0.15

Explanation:

6) (a) Absorbance

Beer's Law is

$A = \epsilon cl\\A = \text{35.9 L&\cdot$mol$^{-1}$cm$^{-1}$} $\times$ 0.0278 mol$\cdot$L$^{-1} \times $ 0.5 cm = \mathbf{0.499}$

(b) Percent transmission

$A = \log {\left (\dfrac{1}{T}}\right)}\\\\\%T = 100T\\\\T = \dfrac{\%T}{100}\\\\\dfrac{1}{T} = \dfrac{100 }{\%T}\\\\A = \log \left(\dfrac{100 }{\%T} \right ) = 2 - \log \%T\\\\0.499 = 2 - \log \%T\\\\\log \%T = 2 - 0.499 = 1.501\\\\\%T = 10^{1.501} = \mathbf{31.7}$

7) Absorbance

$A = \log \left (\dfrac{I_{0}}{I} \right ) = \log \left (\dfrac{I_{0}}{0.70I_{0}} \right ) = \log \left (\dfrac{1}{0.70} \right ) = -\log(0.70) = \mathbf{0.15}}$

8 0

3 years ago

How many cu atoms are present in a piece of sterlingsilver jewelry weighing 33.24 g ? (sterling silver is a silver–copper alloy

emmasim [6.3K]

The mass of piece of sterling silver jewelry is 33.24 g. It contains 92.5% silver Ag by mass. Since, sterling silver is an alloy of Ag-Cu thus, percentage of Cu will be:

% Cu=100-92.5=7.5%

Thus, mass of copper will be:

$m_{Cu}=\frac{7.5}{100}\times 33.24 g=2.493 g$

Molar mass of Cu is 63.546 g/mol, thus, number of moles of Cu can be calculated as follows:

$n=\frac{m}{M}$

Here, m is mass and M is molar mass.

Putting the values,

$n=\frac{2.493 g}{63.546 g/mol}=0.03923 mol$

Now, in 1 mole of Cu there are $6.303\times 10^{23}atoms$ thus, in 0.03923 mol, number of Cu atoms will be:

$0.03923 mol\times 6.303\times 10^{23}atoms=2.363\times 10^{22} atoms$

Thus, number of atoms of Cu will be $2.363\times 10^{22} atoms$ .

8 0

3 years ago

For most substances,the distance between particles is furthest when the substance is?

valentinak56 [21]

Im not positive but i think it is When it is a gas?

3 0

3 years ago

You carefully weigh out 11.00 g of caco3 powder and add it to 44.55 g of hcl solution. you notice bubbles as a reaction takes pl

Zinaida [17]

The bubbles that were observed after the mixing of the two substances is one of the products of the reaction. It is the carbon dioxide that is produced. To determine the mass of this gas produced, we need to remember the Law of conservation of mass where mass cannot be created or destroyed. With this, we can say that the total mass that goes in a process should be equal to the mass that is goes out of the process no matter what the reaction is. We do as follows:

Mass of reactants = mass of products
11.00 + 44.55 = 51.04 + mass of carbon dioxide
mass of carbon dioxide = 4.51 g

8 0

4 years ago