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mario62 [17]
3 years ago
10

Scientists frequently use all of the following to support the theory that organisms change over time except.

Chemistry
2 answers:
Pie3 years ago
8 0

Answer:

4

Explanation:

uranmaximum [27]3 years ago
3 0

Answer:

3

Explanation: google

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Cora, an electrician, wraps a copper wire with a thick plastic coating. What is she most likely trying to do? keep the electric
Alekssandra [29.7K]

Answer: keep a current from passing out of the wire

Explanation: plastic is an insulator and will not conduct electricity

3 0
3 years ago
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Which elements are metalloids? Check all that apply.
Finger [1]
<h3>Answer:</h3>
  • Boron
  • Silicon
  • Tellurium
<h3>Explanation:</h3>
  • Elements in the periodic table are either metals, non-metals or metalloids.
  • Metals are elements that react by losing electron(s) to attain an octet configuration. They occupy groups I, II and III of the periodic table and the transition metals.
  • Non-metals, on the other hand, are elements that react by gaining electron(s) to attain a stable configuration. Examples include halogens and noble gases among others.
  • Metalloids are elements in the periodic table that have the properties of both metals and non-metals.
  • Other examples of metalloids are arsenic, tellurium, germanium and polonium.
7 0
3 years ago
Read 2 more answers
In a gas grill, 29 lbs propane C3H8 are
dimulka [17.4K]

Answer : The mass of combustion products formed are 134 lbs.

Explanation :

The balanced chemical reaction will be:

C_3H_8+5O_2\rightarrow 3CO_2+4H_2O

Given :

Mass of C_3H_8 = 29 lbs = 13154.2 g

conversion used : 1 lbs = 453.592 g

Molar mass of C_3H_8 = 44 g/mole

First we have to calculate the moles of C_3H_8.

\text{ Moles of }C_3H_8=\frac{\text{ Mass of }C_3H_8}{\text{ Molar mass of }C_3H_8}=\frac{13154.2g}{44g/mole}=298.9moles

Now we have to calculate the moles of CO_2 and H_2O.

From the balanced chemical reaction we conclude that,

As, 1 mole of C_3H_8 react to give 3 moles of CO_2

So, 298.9 mole of C_3H_8 react to give 298.9\times 3=896.7 moles of CO_2

and,

As, 1 mole of C_3H_8 react to give 4 moles of H_2O

So, 298.9 mole of C_3H_8 react to give 298.9\times 4=1195.6 moles of H_2O

Now we have to calculate the mass of CO_2 and H_2O.

Molar mass of CO_2 = 44 g/mole

Molar mass of H_2O = 18 g/mole

\text{Mass of }CO_2=\text{Moles of }CO_2\times \text{Molar mass }CO_2

\text{Mass of }CO_2=896.7mole\times 44g/mole=39454.8g=86.98lbs

and,

\text{Mass of }H_2O=\text{Moles of }H_2O\times \text{Molar mass }H_2O

\text{Mass of }H_2O=1195.6mole\times 18g/mole=21520.8g=47.44lbs

The total mass of products = Mass of CO_2 + Mass of H_2O

The total mass of products = 86.98 + 47.44 = 134.42 ≈ 134 lbs

Therefore, the mass of combustion products formed are 134 lbs.

6 0
3 years ago
Does the mass of the sealed jar and its contents change upon the vaporization of the liquid?
Norma-Jean [14]

The answer is No. That is the mass of the sealed jar and its contents does not change upon the vaporization of the liquid, as according to the “law of conservation of mass” , the mass remain conserved when no matter is escape, the mass will remain constant and here also as the jar is sealed, no matter is escaped thus no mass change will be there.

4 0
3 years ago
In CaCo3 + HCl = CaCl2 + H2O +CO3, how many liters of carbon dioxide gas, measured at STP, can be obtained from 45.0 g of calciu
Anon25 [30]

Answer:

B) 10.1 L

Explanation:

Hello,

In this case, for the given chemical reaction which should be corrected as shown below:

CaCO_3 + HCl \rightarrow CaCl_2 + H_2O +CO_2

Since 45.0g of calcium carbonate are used, the produced moles of carbon dioxide, via stoichiometry, are found to be:

n_{CO_2}=45.0g CaCO_3*\frac{1molCaCO_3}{100gCaCO_3}*\frac{1molCO_2}{1molCaCO_3}=0.45molCO_2

Finally, since STP conditions are referred to a temperature of 273.15K and 1 atm, the volume, by using the ideal gas equation result:

V=\frac{nRT}{P}=\frac{0.45mol*0.082\frac{atm*L}{mol*K}*273.15K }{1atm} \\ \\V=10.1L

So the answer is B) 10.1 L.

Best regards.

6 0
3 years ago
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