Which condensed structural formula represents an unsaturated compound?(1) CH3CHCHCH3
(2) CH3CH2CH3
(3) CH3CH3
(4) CH4

Answer : Gaseous water molecules condense when they cooled. Liquid water molecules evaporate when they heated.

Explanation :

Condensation : It is a process in which a phase changes from gaseous state to liquid state. This process occurs when the water molecules in the air cool down and they join together to form liquid water.

Evaporation : It is a process in which a phase changes from liquid state to gaseous state. This process occurs when the water is heated, the molecules in the water move and vibrate quickly that they escape into the atmosphere as water vapor.

Answer:

Five significant figures

Explanation:

You have to change the number to standard form

340500 = 3.405×10**5

** means raise to power

10**5

Where five represents the number of significant figures.

Answer:

4!

Explanation:

benefits :

less time & effort with high numbers

ensures survival of species if no partners available

disadvantages:

less diversity: all offspring could be susceptible to the same disease

evolution is limited

The Testing of the initial version is carried out in the third stage to determine what needs to be improved, while the testing of the beta version is carried out during the fourth stage to ensure that all necessary criteria are met.

The process of technological design involves several distinctive processes which can be broken down into four stages.

The four stages involved in the  process of technological design are :

• Identify a need : during this process the engineer identifies a problem that needs to be resolved
• design a solution : an initial design is created to provide a solution to the problem identified in stage 1
• Implement the solution : The design is tested and implemented if successful
• evaluate the solution : In this stage the result from the solution ( beta version ) is subjectedto ensure that all criteria are met

hence the testing of the initial version is to determine what needs improvement while the testing of the beta version is to ensure all criteria are met

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Answer:

C. The initial version is tested during the third stage to determine what needs to be improved, and the beta version is tested during the fourth stage to ensure that criteria are met.

Explanation:

Edge 2021

Final answer:

The question pertains to the concept of specific heat capacity. Using the formula 'q = mcΔT' where 'q' is the heat transferred, 'm' is the mass of the substance, 'c' is the specific heat and 'ΔT' is the temperature change, we can calculate how much heat a block of iron would release when it cools.

Explanation:

To solve your question, we need to understand the concept of specific heat capacity, which is an intensive property that depends only on the type of substance absorbing or releasing heat. The specific heat capacity (c) of a substance, commonly called its "specific heat," is the quantity of heat required to raise the temperature of 1 gram of the substance by 1 degree Celsius. The specific heat of iron is :

0.449 J/g°C

To calculate the amount of heat released, we need to use the formula for heat transfer as follows:  q = mcΔT where:

• q is the heat transferred
• m is the mass of the substance
• c is the specific heat of the substance
• ΔT is the change in temperature

In this case, the mass of iron is 1.49 kg or 1490 g, the specific heat capacity of iron is 0.449 J/g°C, and the change in temperature is 155°C - 22°C = 133°C.

By multipying these values in the formula we get: q = 1490g x 0.449 J/g°C x 133°C. Therefore, the block of iron would release calculated amount of Joules of heat as it cooled from 155°C to 22°C.

Learn more about specific heat capacity here:

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Answer:

2.53 grams of hydrogen gas will be produced and 12.2 many grams of the excess reactant i.e. calcium will be left over.

Explanation:

Moles of calcium =

Moles of HCl =

According to reaction, 2 moles of HCl reacts with 1 mole of calcium :

Then 2.53 moles of HCl will recat with :

of calcium.

As we can see moles of calcium are in excessive amount. Hence calcium is an excessive reagent.

Moles of calcium left unreacted =1.57 mol - 1.265 mol =0.305 mol

Mass calcium left unreacted = 0.305 mol × 40 g/mol =12.2 g

Since, calcium is an excessive reagent HCl is limiting reagent and the amount of hydrogen gas produced will depend on HCl .

According to reaction, 2 moles of HCl gives 1 mole of hydrogen gas.

Then 2.53 moles of HCl will give:

of hydrogen gas.

Mass of 1.265 mol of hydrogen gas = 1.265 mol × 2 g/mol = 2.53 g

2.53 grams of hydrogen gas will be produced and 12.2 many grams of the excess reactant i.e. calcium will be left over.

Answer:

2.55 g of hydrogen

12.17 g calcium.

to nearest hundredth.

Explanation:

The balanced equation is:

Ca + 2HCl --->   CaCl2 + H2

Using the atomic masses

40.078 g Ca react with 72.916 g of HCl to give 2.016 g HCl

The ratio of Ca to HCl in the above is 1 to 1.81935

so 62.8 g Ca reacts with 62.8 * 1.81935 = 114.245 g HCl

so there is excess of Ca in the  given weights.

Therefore the mass of Hydrogen produced

=  (2.016 / 72.916) * 92.3

= 2.552 g of hydrogen gas.

The mass of calcium required to produce 2.552 g of hydrogen is:

(2.552 /  2.016) * 40.078

= 50.73 g

So the excess of calcium is 62.8 - 50.73

= 12.17 g.