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2 years ago

HELP !!! urgent

Chemistry

1 answer:

NISA [10]2 years ago

7 0

Answer:

carbon monoxide (CO)

Explanation:

carbon monoxide (CO) is oxidized because it gains oxygen to turn to carbon dioxide (CO2)

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(a) Calculate the density of a 374.5-g sample of copper if it has a volume of 41.8 cm3. (b) A student needs 15.0 g of ethanol fo

o-na [289]

Answer:

For a: The density of the sample of copper is $8.96g/cm^3$

For b: The volume of ethanol needed is 19.0 mL

For c: The mass of mercury is 340. grams

Explanation:

To calculate density of a substance, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$ ......(1)

For a:

Mass of copper = 374.5 g

Volume of copper = $41.8cm^3$

Putting values in equation 1, we get:

$\text{Density of copper}=\frac{374.5g}{41.8cm^3}\\\\\text{Density of copper}=8.96g/cm^3$

Hence, the density of the sample of copper is $8.96g/cm^3$

For b:

Mass of ethanol = 15.0 g

Density of ethanol = 0.789 g/mL

Putting values in equation 1, we get:

$0.789g/mL=\frac{15.0g}{\text{Volume of ethanol}}\\\\\text{Volume of ethanol}=\frac{15.0g}{0.789g/mL}=19.0mL$

Hence, the volume of ethanol needed is 19.0 mL

For c:

Volume of mercury = 25.0 mL

Density of mercury = 13.6 g/mL

Putting values in equation 1, we get:

$13.6g/mL=\frac{\text{Mass of mercury}}{25.0mL}\\\\\text{Mass of mercury}=(13.6g/mL\times 25.0mL)=340.g$

Hence, the mass of mercury is 340. grams

5 0

3 years ago

How many atoms of iodine are in 12.75g of CaI2

dexar [7]

Answer:

0.5 × 10²³ atoms of iodine

Explanation:

Given data:

Mass of calcium iodide = 12.75 g

Number of atoms of iodine = ?

Solution:

First of all we will calculate the number of moles of calcium iodide.

Number of moles = mass/ molar mass

Number of moles = 12.75 g/ 293.9 g/mol

Number of moles = 0.04 mol

In one mole of calcium iodide there are two moles of iodine.

Thus in 0.04 moles:

0.04 mol × 2 = 0.08 moles of iodine

Now we will use the Avogadro number:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

0.08 moles of iodine × 6.022 × 10²³ atoms / 1 mol

0.5 × 10²³ atoms of iodine.

8 0

3 years ago

Draw arrows for all of the attractive and repulsive forces between the negatively charged electrons and positively charged proto

Sophie [7]

Answer:

Attraction

(e-) ---> <--- (H+)

Repulsion:

<---(e-) (e-)-->

Neutral:

(e-) (Helium)

Explanation:

Accordingly to coulomb's law:

In the attraction, the hydrogen without an electron has a positive charge and needs to be fulfilled with a negative charge found in an eletron.

In the repulsion, both electrons has the same charge and repulse each other.

In the neutral case, the Helium is highly stable therefore the electron is not attracted.

4 0

3 years ago

Please help ASAP!! (I added a pic)

riadik2000 [5.3K]

The middle is noble gases the first one is alkaline metals and then the last one is the only one left

4 0

3 years ago

Please help thaank youu

krek1111 [17]

First, let's start off by finding the mass of this whole hydrate.
(Note: the unit of measurement for mass will be amu)

Let's find the molecular mass of each element.
$Co=58.933$
$Cl=35.45$
$H=1.008$
$O=15.999$

Now, let's find the mass of each compound.

$CoCl_2=58.933+2(35.45)=129.833$
$H_2O=2(1.008)+15.999=18.015$

We have 6 molecules of H2O, so multiply 18.015 by 6 then add that with the weight of CoCl2.

$6(18.015)=108.09$
$129.833+108.09=237.923$

Now divide 108.09 (mass of all the H2O in the hydrate) by 237.923 (total mass of hydrate).

$\dfrac{108.09}{237.923}$

$\approx0.45431$

Turn that into a percentage and you get 45.431%.
Hope this helps! :)

6 0

3 years ago