1.26 * 10^4 + 2.50 * 10^4 in sceintific notation

2. 7.5 g of potassium react with water to produce potassium hydroxide and hydrogen gas. Calculate the mass of potassium hydroxid

luda_lava [24]

Answer:

10.7 g of KOH

Explanation:

First of all, we determine the reaction:

2K (s) + 2H₂O(l) → H₂(g) + 2KOH(aq)

We convert the mass of K, to moles → 7.5 g . mol/39.1 g = 0.192 moles

Ratio is 2:2, so the moles I have of K must produce the same moles of KOH. In this case, the produces moles of KOH are 0.192 moles.

We convert the moles to mass, to finish the answer:

0.192 mol . 56.1g /1mol = 10.7 g of KOH

8 0

3 years ago

Please help me this is due by midnight!!

mamaluj [8]

Answer:

c

Explanation:

4 0

2 years ago

If the mass of a certain block is 500g, what is the weight of the block?

Dafna11 [192]

______________________________

Solution,

Mass=500g =500/1000=0.5 kg

gravity(g)=9.8m/s^2

Now,

Weight= m*g

 = 0.5*9.8

 =4.9 N

So the weight of the block is 4.9 Newton

hope it helps...

Good luck on your assignment

_______________________

5 0

3 years ago

A 104 m3 thoroughly mixed pond has a water inflow and outflow of 5 m3/h. The inflow water contains 0.01 mol/m3 of chemical. Chem

Naily [24]

Answer:

C ≈ 1.44 × 10⁻³ mol/m³

Explanation:

The given information are;

The liquid volume the pond can hold = 104 m³

The volume of inflow into the pond = 5 m³/h

The volume of outflow into the pond = 5 m³/h

The concentration of the chemical in the inflow water = 0.01 mol/m³

The concentration of the chemical discharged directly into the water = 0.1 mol/h

The concentration, $c_{(inflow)}$ , of chemical that enters the water through inflow per hour is given as follows;

$c_{(inflow)}$ = 0.01 mol/m³ × 5 m³/h = 0.05 mol/h

The concentration, $c_{(discharge)}$ , of chemical that enters the water through direct discharge per hour is given as follows;

$c_{(discharge)}$ = 0.1 mol/h

The total concentration that enters the pond per hour is given as follows;

$c_{(inflow)}$ + $c_{(discharge)}$ = 0.1 mol/h + 0.05 mol/h = 0.15 mol/h

Whereby the water in the pond properly mixes with the pond, we have;

The concentration of chemicals (C) in the outflow water = 0.15 mol/(104 m³) ≈ 0.00144 mol/m³

C ≈ 1.44 × 10⁻³ mol/m³.

4 0

3 years ago

Use the drop-down menus to complete each sentence.

Ipatiy [6.2K]

Explanation:

Elements that belong to same group contains same number of valence electrons. Hence, they tend to show similar chemical properties.

When we move across a period then number of electrons get added to the same shell. As a result, there will be no increase in size of elements.

Also, metals are the elements that belong to group 1, 2 and d-block elements are also known as metals. Metallic character of elements decreases when we move left to right in a periodic table.

As most reactive metals are placed on the left side of periodic table.

Since, size of elements increases on moving down the group. So, an element is able to easily lose its valence electrons because of less force of attraction between its nucleus and valence electrons.

As a result, there will be increase in reactivity of metals on moving down the group.

Thus, we can conclude that given sentences are as follows.

Elements in the same group have the same number of valence electrons.

Elements in the same period have the same number of electron shells.

Metallic elements become less reactive as you move left to right in a period.

Metallic elements become more reactive as you move top to bottom in a group.

3 0

3 years ago

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