ANSWER FAST PLZ 25 POINTS!!!!!!!!!!!!!!!

Im dum.b help

nordsb [41]

Answer:

2.A baby grasshoper is a nymph.

Explanation:

8 0

3 years ago

Read 2 more answers

Whoever awser correct I will give you Brainly

vivado [14]

Answer:

Option A.

2Na + 2H2O —> 2NaOH + H2

Explanation:

To know which option is correct, we shall do a head count of the number of atoms present on both side to see which of them is balanced. This is illustrated below below:

For Option A:

2Na + 2H2O —> 2NaOH + H2

Reactant >>>>>>> Product

2 Na >>>>>>>>>>> 2 Na

4 H >>>>>>>>>>>> 4 H

2 O >>>>>>>>>>>> 2 O

Thus, the above equation is balanced.

For Option B:

2Na + 2H2O —> NaOH + H2

Reactant >>>>>>> Product

2 Na >>>>>>>>>>> 1 Na

4 H >>>>>>>>>>>> 3 H

2 O >>>>>>>>>>>> 1 O

Thus, the above equation is not balanced.

For Option C:

2Na + H2O —> 2NaOH + H2

Reactant >>>>>>> Product

2 Na >>>>>>>>>>> 2 Na

2 H >>>>>>>>>>>> 4 H

1 O >>>>>>>>>>>> 2 O

Thus, the above equation is not balanced.

For Option D:

Na + 2H2O —> NaOH + 2H2

Reactant >>>>>>> Product

1 Na >>>>>>>>>>> 1 Na

4 H >>>>>>>>>>>> 5 H

2 O >>>>>>>>>>>> 1 O

Thus, the above equation is not balanced.

From the illustrations made above, only option A is balanced.

7 0

3 years ago

Which of the following statements a about scientific hypothesis is false?

Pachacha [2.7K]

Answer:

The false statement from the given statements is option a.

Explanation:

Hypothesis:

A hypothesis is a intelligent guess or prediction to interpret or explain any phenomena.

It is tested through the series of experiments and by number of studies to actually decide whether hypothesis is in agreement with observation and results predicted by it. These prediction are made on basis of limited evidences. It can be false or true.

Theory:

A theory is an in depth explanation behind any physical phenomena which has been tested multiple times through the correct scientific methods and experimentation. It will give same results and observations.

7 0

3 years ago

1.How many mL of 0.523 M HBr are needed to dissolve 8.60 g of CaCO3?

prohojiy [21]

Answer:

The answer to your question is:

Explanation:

1.-

HBr = 0.523 M V = ?

CaCO3 = 8.6 g

2HBr(aq) + CaCO₃(s) ⇒ CaBr₂(aq) + H₂O(l) + CO₂(g)

MW CaCO₃ = 40 + 12 + 48 = 100 g

MW HBr = 80 + 1 = 81 g

Molarity = moles / volume

100 g of CaCO₃ ---------------- 1 mol

8.6 g ---------------- x

x = (8.6 x 1) / 100

x = 0.086 moles

2 moles of HBr ----------------- 1 mol of CaCO₃

x ----------------- 0.086 moles

x = (0.086 x 2) / 1 = 0.172 moles of HBr

Volume = moles / molarity

Volume = 0.172/ 0.523 = 0.323 l or 323 ml of HBr

2.-

V = ? ml NaOH 0.487 M

V = 101 ml of 0.628 M MnSO₄

MnSO₄(aq) + 2NaOH(aq) ⇒ Mn(OH)₂(s) + Na₂SO₄(aq)

MW MnSO₄ = 55 g

MW NaOH = NaOH = 40 g

Moles = Molarity x volume

Moles = (0.628) x (0.101)

Moles = 0.065 moles of MnSO₄

1 mol of MnSO₄ ------------------ 2 moles of NaOH

0.065 ----------------- x

x = (0.065x 2) / 1

x = 0.131 moles of NaOH

Volume = moles / molarity

Volume = 0.131 / 0.487

Volume = 0.268 l or 268 ml of NaOH

4 0

3 years ago

A chemist needs 10 liters of a 25% acid solution. The solution is to be mixed from three solutions whose concentrations are 10%,

mojhsa [17]

Answer:

a) 1 litre of 10% solution and 7 litre of 20% solution

b) 1.67 litres of 50% solution and 8.33 litres of the 20% solution

c) 3.75 litres of 50% solution and 6.25 litres of 20% solution

Explanation:

Given:

chemist needs = 10 liters of a 25% acid solution

Concentration of three solutions that are to be mixed = 10%, 20% and 50%.

Solution:

A) Use 2 liters of the 50% solution

Let us mix this with 10% and 20% solution

They will have to equal 8 litres

Let x=20% solution

Then (8-x) =10%

So the equation becomes,

10%(8-x)+ 20%x+50%(2)=25(10)

(0.1)(8-x) +0.2x+0.50(2)= 0.25(10)

0.8-0.1x+0.2x+1.0=2.5

0.2x-0.1x=2.5-0.8-1.0

0.1x=0.7

$x=\frac{0.7}{0.1}$

x= 7

so, 8-x = 8 -7= 1 litre of 10% solution and 7 litre of 20% solution

B)Use as little as possible of the 50% solution

Let x be the amount of 50% solution.

Then(10-x) be the 20% solution

Now the equation becomes,

50%(x)+20%(10-x)=25%(10)

0.50x+0.2(10-x)=0.25(10)

0.5x+2.0-0.2x=2.5

0.3x=2.5-2.0

0.3x=0.5

$x=\frac{0.5}{0.3}$

x=1.67

now (10-x)=(10-1.67)=8.33

so there will be 1.67 litres of 50% solution and 8.33 litres of the 20% solution

c) ) Use as much as possible of the 50% solution

Let x be the amount of 50% solution.

Then(10-x) be the 20% solution

Now the equation becomes,

50%(x)+10%(10-x)=25%(10)

0.50x+0.1(10-x)=0.25(10)

0.5x+1.0-0.1x=2.5

0.4x=2.5-1.0

0.4x=1.5

$x=\frac{1.5}{0.3}$

x=3.75

Now, (10-x)=(10- 3.75)=6.26

So there will be 3.75 litres of 50% solution and 6.25 litres of 20% solution

5 0

3 years ago