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3 years ago

A 50-mL beaker only has a scale that measures 10, 20, 30, and 40 mL. What is the uncertainty associated with the 50 mL beaker.

1 answer:

8 0

If the uncertainty of a certain measurement instrument is not given, then it is assumed to be equal to half of the least count of that instrument. In this case, the least count is 10 ml, so half of this is 5 ml. Therefore, the graduated cylinder has an uncertainty of +/- 5 ml

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In the background information, it was stated that CaF2 has solubility, at room temperature, of 0.00160 g per 100 g of water. How

____ [38]

Answer:

2.05*10⁻⁵ moles of CF₂ can dissolve in 100 g of water.

12.82 moles of CaF₂ will dissolve in exactly 1.00 L of solution

Explanation:

First, by definition of solubility, in 100 g of water there are 0.0016 g of CaF₂. So, to know how many moles are 0.0016 g, you must know the molar mass of the compound. For that you know:

Ca: 40 g/mole
F: 19 g/mole

So the molar mass of CaF₂ is:

CaF₂= 40 g/mole + 2*19 g/mole= 78 g/mole

Now you can apply the following rule of three: if there are 78 grams of CaF₂ in 1 mole, in 0.0016 grams of the compound how many moles are there?

$moles=\frac{0.0016 grams*1 mole}{78 grams}$

moles=2.05*10⁻⁵

<u><em>2.05*10⁻⁵ moles of CF₂ can dissolve in 100 g of water.</em></u>

Now, to answer the following question, you can apply the following rule of three: if by definition of density in 1 mL there is 1 g of CaF₂, in 1000 mL (where 1L = 1000mL) how much mass of the compound is there?

$mass of CaF_{2}=\frac{1000 mL*1g}{1mL}$

mass of CaF₂= 1000 g

Now you can apply the following rule of three: if there are 78 grams of CaF₂ in 1 mole, in 1000 grams of the compound how many moles are there?

$moles=\frac{1000 grams*1 mole}{78 grams}$

moles=12.82

<u><em>12.82 moles of CaF₂ will dissolve in exactly 1.00 L of solution</em></u>

5 0

3 years ago

NEED HELP FAST I WILL MARK BRAINLIEST AND THANK YOU AND RATE 5 STARS.

sleet_krkn [62]

Hello there,

All compounds of carbon are made by <span>ionic bonding.

I Hope this helps.

~Jurgen</span>

5 0

3 years ago

Read 2 more answers

A chemical engineer determines the mass percent of iron in an ore sample by converting the Fe to Fe²⁺ in acid and then titrating

neonofarm [45]

The mass percent of iron in the ore is 31.6%

<h3>Steps</h3>

8H⁺(aq) + 5Fe²⁺(aq) + MnO⁻₄(aq) → 5Fe³⁺(aq) + Mn²⁺(aq) + 4H₂O(l)

V(MnO4^-)=39,32 mL

c(MnO4^-)=0,0319M

n(MnO4^-)=c*V=1,254308 mmol

n(Fe^{2+})=5*n(MnO4^-)=6,27 mmol

Equation

Fe+2H->Fe^+2 + H2

n(Fe)=n(Fe^{2+} )=6,27 mmol

m(Fe)=n*Ar=350,27mg=0,35027g

mass percent(Fe in ore)=m(Fe)/m(ore)*100

=31,61 percent

The mass percent of iron in the ore is 31.6%

<h3>What is the equation for the balance formula?</h3>

An equation for a chemical reaction is said to be balanced if both the reactants and the products have the same number of atoms and total charge for each component of the reaction. In other words, both sides of the reaction have an equal balance of mass and charge.

<h3>An illustration of a balanced equation</h3>

For instance, consider about the reaction: O2 (g) + 2Mg(s) = 2MgO (g) Two magnesium and two oxygen atoms are present in this reaction on both the reactant and product sides.

learn more about balanced equation here

brainly.com/question/26694427

#SPJ4

8 0

1 year ago

What is the diffrence between acidic and basic solutions in working with redox reactions?

Leno4ka [110]

In acidic solutions you have H+ but in basic solutions you have OH-.
You need know that for to balance the reaction.

3 0

3 years ago

True or Flase: dissolving salt in distilled water creates a homogeneous mixture.

chubhunter [2.5K]