Which of the following statements is true regarding scientific hypotheses?

Why do reactivity increases on moving from top to bottom in group 2 of modern periodic table?

Nikolay [14]

Answer:

that's because....

group 1 (e.g Na, K) those tend to lose one electron to gain noble gas electron configuration.

they can achieve that by just losing one electron from their outer shell.

as you go down the group 1, element gets bigger in size, which means there is more space between nucleus (which is in center of atom) and electron of outer shell. the more far away they are the less attraction force between them.

so its easier for potassuim to lose one electron than for lithuim.

so that means potassium will easily give up 1 electron to react with non metal or other element therefore it is more reactive than lithuim

but in case of non metal, the opposite happens but simple to understand.

as you go down the group 7 (halogen- Cl, Br, I) element will get bigger therefore force between nucleus and outer electron is getting smaller. they have to gain 1 electron in order to fill the outer shell (to gain noble gas electron configuration.)

as florine is more smaller in size than clorine it is more reactive because florine has more tendency to pull extra electron from metal or other element towards its side. so it easily gain 1 electron to react.

3 0

3 years ago

A chemical reaction can theoretically produce 1375.5 grams of product , but in actuality 112.9 grams are product . Which is the

zalisa [80]

Answer:

8.20 % → Percent yield reaction

Explanation:

To find the percent yield of reaction we apply this:

(Produced yield / Theoretical yield) . 100 = %

Produced yield = 112.9 g

Theoretical yield = 1375.5 g

We replace → (112.9g / 1375.5 g) . 100

8.20 % → Percent yield reaction

3 0

3 years ago

A pan containing 20.0 grams of water was allowed to cool from a temperature of 95.0 °C. If the amount of heat released is 1,200

34kurt

Answer:

81 °C

Explanation:

This is a calorimetry question so a few things you will need for this. The calorimetry equation q=mcΔT & the specific heat of water (4.2J/g•°C). Other definitions are:

q = heat added/released by a sample

m = mass of sample

c=specific heat of sample

ΔT = change in temperature

from here we can rearrange the equation to state:

q/(mc) = ΔT

1200J/((20.0g)(4.2J/g•°C)) = ΔT

14°C = ΔT

If the starting temperature was 95.0°C and we know that the temperature was cooled by 14°C then the final temperature of the water would be 81.

4 0

2 years ago

Start with 100.00 mL of 0.10 M acetic acid, CH3COOH. The solution has a pH of 2.87 at 25 oC. a) Calculate the Ka of acetic acid