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2 years ago

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1 answer:

sleet_krkn [62]2 years ago

8 0

Answer:

Magnesium and calcium belong to the second group i. e. alkaline earth metals. They are known as earth metals because they are extracted from the earth. They are very reactive elements. Their reactivity increases when we go from top to bottom because the outermost electrons goes farther from the nucleus i. e. atomic radius increases so less energy is needed for its removal.

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Jill is making lemonade. She mixes together some water, lemon juice, and sugar. The lemonade is classified as a(n) _________. A)

PolarNik [594]

Hello, Thanks for making your post on brainly!

I would say the best answer is C)Mixture

A mixer is made by combining 2 or more elements, but your not making a new element. And there are no chemical reactions happening to make a new element.

Hope this helps. Have a great day.

8 0

2 years ago

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Which two options are examples of waves refecting

sergey [27]

Answer:

A voice echo

Your image in a mirror

Explanation:

hope this helps

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2 years ago

HI, I need help my my edg. Can you help me? I will give crown.<br> :D

ahrayia [7]

Answer:

Most liking the puck will go flying because of the force of the hockey stick.

8 0

2 years ago

A reaction of 41.9 g of Na and 30.3 g of Br2 yields 36.4 g of NaBr . What is the percent yield?

Licemer1 [7]

Answer: The percent yield is, 93.4%

Explanation:

First we have to calculate the moles of Na.

$\text{Moles of Na}=\frac{\text{Mass of Na}}{\text{Molar mass of Na}}=\frac{41.9g}{23g/mole}=1.82moles$

Now we have to calculate the moles of $Br_2$

${\text{Moles of}Br_2} = \frac{\text{Mass of }Br_2 }{\text{Molar mass of} Br_2} =\frac{30.3g}{160g/mole}=0.189moles$

${\text{Moles of } NaBr} = \frac{\text{Mass of } NaBr }{\text{Molar mass of } NaBr} =\frac{36.4g}{103g/mole}=0.353moles$

The balanced chemical reaction is,

$2Na(s)+Br_2(g)\rightarrow 2NaBr$

As, 1 mole of bromine react with = 2 moles of Sodium

So, 0.189 moles of bromine react with = $\frac{2}{1}\times 0.189=0.378$ moles of Sodium

Thus bromine is the limiting reagent as it limits the formation of product and Na is the excess reagent.

As, 1 mole of bromine give = 2 moles of Sodium bromide

So, 0.189 moles of bromine give = $\frac{2}{1}\times 0.189=0.378$ moles of Sodium bromide

Now we have to calculate the percent yield of reaction

$\%\text{ yield}=\frac{\text{Actual yield}}{\text{Theoretical yield}}\times 100=\frac{0.353 mol}{0.378}\times 100=93.4\%$

Therefore, the percent yield is, 93.4%

3 0

2 years ago

If a car travels 400m in 20 seconds, how fast is it going

prohojiy [21]

Answer:

Just apply the formula

speed = distance/ time

= 400/20

= 20 m/s

this is the way to do it

3 0

2 years ago

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