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3 years ago

13

What value must be known if the accuracy of an experiment is to be determined

1 answer:

andrezito [222]3 years ago

7 0

To evaluate the accuracy of a measurement, the measured value must be compared to the correct value. To evaluate the precision of a measurement, you must compare the values of two or more repeated measurements.

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In general, which properties are common to elements within a single group on the periodic table?

blsea [12.9K]

Almost all properties are common to elements within a single group on the periodic table. They react with water in the same way, they have the same number of valence electrons thereby having the same valency, the number of shells in the atom of the element increases by one as we move down the group.

In general, they have the same chemical properties as chemical properties depend on the number of electrons in the valence shell i.e. the outermost shell in the atom of an element.

7 0

4 years ago

How many molecules of CBr4 are in 250 grams of CBr4

Kazeer [188]

Answer:- $4.54*10^2^3$ molecules.

Solution:- The grams of tetrabromomethane are given and it asks to calculate the number of molecules.

It is a two step unit conversion problem. In the first step, grams are converted to moles on dividing the grams by molar mass.

In second step, the moles are converted to molecules on multiplying by Avogadro number.

Molar mass of $CBr_4$ = 12+4(79.9) = 331.6 g per mol

let's make the set up using dimensional analysis:

$250g(\frac{1mol}{331.6g})(\frac{6.022*10^2^3molecules}{1mol})$

= $4.54*10^2^3$ molecules

So, there will be $4.54*10^2^3$ molecules in 250 grams of $CBr_4$ .

8 0

3 years ago

The concentration of Rn−222 in the basement of a house is 1.45 × 10−6 mol/L. Assume the air remains static and calculate the con

bonufazy [111]

<u>Answer:</u> The concentration of radon after the given time is $3.83\times 10^{-30}mol/L$

<u>Explanation:</u>

All the radioactive reactions follows first order kinetics.

The equation used to calculate half life for first order kinetics:

$t_{1/2}=\frac{0.693}{k}$

We are given:

$t_{1/2}=3.82days$

Putting values in above equation, we get:

$k=\frac{0.693}{3.82}=0.181days^{-1}$

Rate law expression for first order kinetics is given by the equation:

$k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}$

where,

k = rate constant = $0.181days^{-1}$

t = time taken for decay process = 3.00 days

$[A_o]$ = initial amount of the reactant = $1.45\times 10^{-6}mol/L$

[A] = amount left after decay process = ?

Putting values in above equation, we get:

$0.181days^{-1}=\frac{2.303}{3.00days}\log\frac{1.45\times 10^{-6}}{[A]}$

$[A]=3.83\times 10^{-30}mol/L$

Hence, the concentration of radon after the given time is $3.83\times 10^{-30}mol/L$

7 0

4 years ago

3. How fast will her 1500 kg car accelerate if it produces 5000 N of force?

andrew-mc [135]

Answer:

just add 1500 to 5000

Explanation:

5 0

3 years ago

Fusion is a type of chemical reaction true or false

Ivanshal [37]

Fusion is not a type of chemical reaction. False.

4 0

3 years ago

Read 2 more answers