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3 years ago

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Chemistry

2 answers:

luda_lava [24]3 years ago

7 0

The sum is 34.688 m.

If m is a variable, then the m would be attached to 34.688.

aalyn [17]3 years ago

3 0

When you add each of the numbers, you get the number 34.668. However, you have to remember to put the answer to the right number of significant figures. To do this, you have to look at the three numbers you added, and the answer must have the same number of decimal places as the addend with the lowest number of decimal places. In this case, the lowest number of decimal places is one (in the number 16.2), therefore; you have to round 34.688 to one decimal place, which would be 34.7 and just put that variable right back in front. So the final answer is 34.7m

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What was John Dobereiner’s contribution to the development of the periodic table

erastova [34]

John Dobereiner proposed the idea of similarity in the properties of elements which can be placed together.

He proposed the idea of classification so that we can study the properties of a group of elements together

According to him, three elements can be grouped based on their similarities in properties. This group of three elements was termed as "Triads"

For example :

Li, Na, K

Now the significance of the triad was that the atomic weight of middle element is average of atomic weights of the side atoms

So atomic weight of Na = 23 is average of atomic weights of Lithium and Potassium

7 + 39/2 = 46/2= 23

The other triads were

Ca Sr Ba

Cl Br I

S Se Te

5 0

4 years ago

a sample of cobalt (specific heat of Co=0.418J/G C )at 100.0 C is dropped into a calorimeter containing 500.0 mL of water at 21.

Alex17521 [72]

Answer:

$m_{Co}=6998g=7.0kg$

Explanation:

Hello there!

In this case, according to this equilibrium temperature problem, we can set up the following equation to relate the mass, specific heat and temperature change:

$Q_{Co}=-Q_{w}\\\\m_{Co}C_{Co}(T_f-T_{Co})=-m_{w}C_{w}(T_f-T_{w})$

Thus, we solve for the mass of cobalt as shown below:

$m_{Co}=\frac{-m_{w}C_{w}(T_f-T_{w})}{C_{Co}(T_f-T_{Co})} \\\\m_{Co}=\frac{-500.00g*4.184J/g\°C(67.1\°C-21.1\°C)}{0.418J/g\°C(67.1\°C-100\°C)} \\\\m_{Co}=6998g=7.0kg$

Best regards!

7 0

3 years ago

What ways is carbon added to the atmosphere

Alinara [238K]

Answer:

One way is through fossil fuels. When people burn fossil fuels it enters the atmosphere as carbon dioxide gas. Another way is through animals. Most animals exhale carbon dioxide as a waste product which gets into the atmosphere.

6 0

3 years ago

Read 2 more answers

Suppose that you obtain 1.0 g of isopentyl acetate from reacting 1.0 mL of acetic acid with 1.0 mL of isopentyl alcohol. Calcula

Elden [556K]

Answer:

83.72%

Explanation:

The equation of of Reaction is given below;

CH3COOH + C5H11OH ------> CH3COOC5H11 + H2O. --------------(1).

The equation (1) shows that one mole of acetic acid react with one mole of isopentyl alcohol to give one mole of isopentyl acetate and one mole of water.

RATIO===> 1 : 1 ------> 1 : 1.

We are given 1.0 mL of acetic acid and 1.0 mL of isopentyl alcohol.

===> Things to know: The density of acetic acid = 1.05 g/cm^3 and the density of isopentyl alcohol= 0.809 g/cm^3, 1 mL = 1 cm^3, molar mass of isopentyl alcohol = 88.179 g/mol.

So, the density of acetic acid = 1.05 g/mL and the density of isopentyl alcohol= 0.809 g/mL.

Therefore, mass of acetic acid;

= 1.0 mL acetic acid ×( 1.05 g/ mL).

= 1.05 g acetic acid.

Mass of isopentyl alcohol= 1.0 mL × 0.809 g/mL = 0.809 grams isopentyl alcohol.

Since one mole of each reactants formed the product, we have to find the limiting reagent. This is done by converting the mass into moles.

Hence, for acetic acid; the number of moles = mass/molar mass.

===> 1.05 grams of acetic acid/ 60.052 g/mol.

===> 0.017485 moles acetic acid.

For isopentyl alcohol; 0.809/ 88.179 grams per mol.

==> 0.0091745 mol isopentyl alcohol.

We can see that isopentyl alcohol is the limiting reagent. So, 0.0091745 mole isopentyl alcohol will produce 0.0091745 mol isopentyl acetate.

Hence, the mass of isopentyl acetate= number of moles × molar mass= 0.0091745 × 130.19 grams per mol.

==> 1.19 grams isopentyl acetate.

FINAL STEP: calculating the percent yield. The actual yield is 1.0 g, theoretical yield = 1.19 grams

Percent yield = actual yield/ theoretical yield × 100.

Percent yied;

= 1.0 grams/ 1.19 grams × 100.

= 83.72 %.

8 0

4 years ago

When she introduced CO(g) and Cl2(g) into a 1.00 L evacuated container, so that the initial partial pressure of CO was 1.86 atm

cupoosta [38]

Answer:

Kp is 0.00177

Explanation:

We state the equilibrium:

CO(g) + Cl₂(g) ⇆ COCl₂(g)

Initially we have these partial pressures

1.86 atm for CO and 1.27 for chlorine.

During the reaction, x pressure has been converted. As we have 0.823 atm as final pressure in the equilibrium for COCl₂, pressure at equilibrium for CO and chlorine will be:

1.86 - x for CO and 1.27 - x for Cl₂.

And x is the pressure generated for the product, because initially we don't have anything from it. So pressure in equilibrium for the reactants will be:

1.86 - 0.823 = 1.037 atm for CO

1.27 - 0.823 = 0.447 atm for Cl₂

Let's make, expression for Kp:

Partial pressure in eq. for COCl₂ / P. pressure in eq. for CO . P pressure in eq. for Cl₂

Kp = 0.823 / (1.037 . 0.447) → 0.00177

5 0

3 years ago