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larisa86 [58]
3 years ago
6

Can someone please name a project I can do for my science fair for 7th grade I need a easy one

Chemistry
1 answer:
avanturin [10]3 years ago
7 0
I know one it is with matter

You can do a mixture by making a fruit salad
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how many moles of water are in 1.23 x 10^18 water molecules? I need the answer in scientific notation ?
Ann [662]

Answer:

Moles=2.04×10^(-6)

Explanation:

No. Of moles=no. Of particles/ Avogadro's no

(Where no. Of particles may be atoms molecules or compounds)

Moles=1.23×10^18/6.022×10^23

Moles=0.204×10^(-5)

Moles=2.04×10^(-6)

8 0
3 years ago
A sample of iron metal is placed in a graduated cylinder. it is noted that 10.4 ml of water is displaced by the iron. the iron i
Pavel [41]
<h3>Answer:</h3>

                 162.43 g of FeCl₂

<h3>Explanation:</h3>

Step 1: Calculate mass of Fe;

As,

                                   Density  =  Mass ÷ Volume

Or,

                                   Mass  =  Density × Volume

Where Volume is the volume of water displaced  =  10.4 mL

Putting values,

                                   Mass  =  7.86 g.mL⁻¹ × 10.4 mL

                                   Mass  =  81.744 g of Fe

Step 2: Calculate amount of FeCl₂;

The balance chemical equation is as follow,

                                Fe  +  2 HCl   →    FeCl₂  +  H₂ ↑

According to this equation,

       55.85 g (1 mol) Fe produced  =  110.98 g (1 mol) of FeCl₂

So,

               81.744 g Fe will produce  =  X g of FeCl₂

Solving for X,

                    X  =  (81.744 g × 110.98 g) ÷ 55.85 g

                     X =  162.43 g of FeCl₂

7 0
3 years ago
Quincy wants to see a real example of rock weathering. Where would be the best place for him to go? A. up on the roof of his hou
zhannawk [14.2K]

Answer:

Option (D)

Explanation:

Weathering is usually defined as the disintegration of rocks at the surface of the earth. This break down of rocks is mainly caused by the geological processes that occur on the earth's surface. This process results in the formation of sediments that are transported and deposited in a new environment.

This weathering process primarily takes place in three different ways such as-

  • Physical weathering- Here, the rocks are broken down by the physical agents such as wind, water, ice.
  • Chemical weathering- Here the rocks are broken down when interacts with the chemical containing water.
  • Biological weathering- here, the rocks are broken down due to the activities done by organisms such as plants and animals.

In the given condition, Quincy can see a real example of rock weathering in the high mountainous region, as in the mountainous region the rocks are frequently weathered and eroded by the agents such as wind, water, and ice.

Thus, the correct answer is option (D).

4 0
3 years ago
What are reasons standardizing conditions in which chemist describe matter?
ExtremeBDS [4]
Matter is the basic unit of every thing in the world, whether living or nonliving. So, it is logical to set definitions and postulates because these could pave way to other complexities of science. It is the foundation of science. That is why theories and laws are formulated for matter such as: Kinetic Theory of Matter, Dalton's Atomic Model, Newton's Law of Motion, Conservation Laws and many more.
7 0
3 years ago
Calculate the ph of a solution formed by mixing 200.0 ml of 0.30 m hclo with 300.0 ml of 0.20 m kclo. the ka for hclo is 2.9 × 1
velikii [3]
C(HClO) = 0,3 M.
<span>V(HClO) = 200 mL = 0,2 L.
n(HClO) = </span>c(HClO) · V(HClO).
n(HClO) = 0,06 mol.<span>
c(KClO</span>) = 0,2 M.
<span>V(KClO) = 0,3 L.
n(KClO) = 0,06 mol.
V(buffer solution) = 0,2 L + 0,3 L = 0,5 L.
ck</span>(HClO) = 0,06 mol ÷ 0,5 L = 0,12 M.
cs(KClO) = 0,06 mol ÷ 0,5 L = 0,12 M.<span>
Ka(HClO</span>) = 2,9·10⁻⁸.<span>
This is buffer solution, so use Henderson–Hasselbalch equation: 
pH = pKa + log(cs</span> ÷ ck).<span>
pH = -log(</span>2,9·10⁻⁸) + log(0,12 M ÷ 0,12 M).<span>
pH = 7,54 + 0.
pH = 7,54</span>
6 0
3 years ago
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