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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
You might be interested in
how do i solve these equations using proust's law? we haven't gone over balancing chem equations in class and our teacher doesn'
kow [346]

Answer:

Explanation:

Ok so Proust's Law, better known as the Law of Definite Proportions, states that the components of a compound always exist in a fixed ratio. This means that it does not matter what the source of the components are nor the coefficients in front of them. The ratio your teacher is referring to is most likely mass percent/ percent composition. This ratio is the amount of the component over the amount of the entire compound times 100%.

*I am not very familiar with this law so please do with my answers what you will :)*

7.)

First, you want to find the percent composition (aka mass composition) of Na in NaCl.

 45.89 g Na
---------------------  x 100%  =  39.3%
116.89 g NaCl

So, there must be 39.3% sodium in NaCl. You can find how much chlorine is in NaCl by subtracting that percent by 100 (to find the percent composition of chlorine) then multiplying it by the mass.

100% - 39.3% = 60.7%

60.7% / 100 = 0.0607

116.89 g NaCl x 0.0607 = 70.91 g Cl₂

You could also just subtract the mass of sodium from the mass of sodium chloride to find the mass of chlorine.

116.89 g NaCl - 45.89 g Na = 71 g Cl₂

8.)

10.57 g Mg + 6.96 g O₂ = 17.53 g MgO

  6.96 g O₂
---------------------  x 100%  = 39.7% O₂
17.53 g MgO

9.)

6.46 g Pb = 1 g O₂

68.54 g Pb  =  28.76 g O₂

68.54 g Pb / 28.76 g O₂ = 2.83 g ≠ 6.46 g

No, the two samples are not the same because the proportion of lead to oxygen is not the same for both samples. In the first sample, there is 6.46 g lead for every oxygen. In the second sample, there is 2.38 g lead for every oxygen.

6 0
1 year ago
assume the given amount of rbf fully dissociates in water. calculate the molarity of a solution if 124.86 g of rbf are dissolved
xeze [42]

Molarity of a solution if 124.86 g of rbf are dissolved into a solution of water that has a final volume of 2.00L is 0.59.

<h3>What is molarity?</h3>

Molarity is used for dilute aqueous solutions held at a constant temperature. In general, the difference between molarity and molality for aqueous solutions near room temperature is very small and it won't really matter whether you use a molar or molal concentration.

MOLARITY = no of moles of solute/volume of soln in litres

No of moles of rbf = 124.6/104.46

= 1.19

Volume of soln = 2

Molarity=1.19/2 = 0.59

Learn more about Molarity here: brainly.com/question/26756988

#SPJ4

5 0
9 months ago
Calculate the number of total atoms in 195 grams of Ni(OH)2.
Anni [7]

1.267 x 10 ^ 24 is the total number of atoms

6 0
3 years ago
Sevin, the commercial name for an insecticide used to protect crops such as cotton, vegetables, and fruit, is made from carbamic
xeze [42]

Answer:

Explanation:

Ratio of mass of C , N , H and O

= .8007 :0.9333:0.2016:2.133

Ratio of moles of C , N , H and O

= .8007/12 : .9333 / 14 : 0.2016 / 1 : 2.133/16

= .0667 : .0667: .2016 : .1333

= .0667 / .0667 : .0667 / .0667 : .2016 /.0667 : .1333 / .0667

= 1 : 1 : 3: 2

Hence empirical formula = CNH₃O₂

7 .

Weight of titanium Ti = 1.916 g

Weight of oxygen = 3.196 - 1.916 = 1.28 g

Ratio of weight of Ti and O

= 1.916 : 1.28

Ratio of moles  of Ti and O

1.916/48 : 1.28/16  [ Molecular  weight of Titanium is 48 ]

= .04 : .08

= .04/.04 : .08/.04

= 1 :2 .

Empirical formula

TiO₂

5 0
2 years ago
How many mm are equal to 21 L. How many mg are equal to 9 g. How many grams are equal to 400 kg
liberstina [14]
<span>How many mm are equal to 21 L? 

1 L = </span>1000000 mm

Convert:-

1000000 × 21 = <span>21000000

21 l = </span><span>21000000 mm

</span><span>How many mg are equal to 9 g?

1 g = 1000 mg

Convert:-

9 </span>× 1000 = 9000

9 g = 9000 mg
8 0
3 years ago
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