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2 years ago

How can a spinning ball have more lift than one that is not spinning?

Chemistry

2 answers:

m_a_m_a [10]2 years ago

8 0

Answer:

A spinning ball creates a "Centrifugal Force" because you give it the "energy" to spin. A ball that is not moving does not require any external energy to keep it still.

Explanation

Alex73 [517]2 years ago

8 0

I think because the spinning one have more kinetic energy I’m not sure

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Calculate the concentration of formate in a 100mm solution of formic acid at ph 4.15. The pka for formic acid is 3.75

MissTica

The molarity of formic acid is 100 mM or $100\times 10^{-3}M$ . The dissociation reaction of formic acid is as follows:

$HCOOH\leftrightharpoons HCOO^{-}+H^{+}$

The expression for dissociation constant of the reaction will be:

$K_{a}=\frac{[HCOO^{-}][H^{+}]}{[HCOOH]}$

Rearranging,

$[HCOO^{-}]=\frac{K_{a}[HCOOH]}{[H^{+}]}$

Here, pH of solution is 4.15 thus, concentration of hydrogen ion will be:

$[H^{+}]=10^{-pH}=10^{-4.15}=7.08\times 10^{-5}M$

Similarly, $pK_{a}=3.75$ thus,

$[K_{a}=10^{-pK_{a}}=10^{-3.75}=1.78\times 10^{-4}M$

Putting the values,

$[HCOO^{-}]=\frac{(1.78\times 10^{-4}M)(100\times 10^{-3}M)}{(7.08\times 10^{-5}M}=0.2511 M$

Therefore, the concentration of formate will be 0.2511 M.

4 0

2 years ago

Question 43 please. i’m not sure if i got the right answer

hram777 [196]

a) The reaction is exothermic since the overall enthalpy change is negative. this means that the system has lost energy to the environment, namely, the apparatus and due to drought.

b) We first calculate the number of moles in 3.55 grams of magnesium.

number of moles= mass/ atomic mass

=3.55/24

=0.1479 moles(to 4sf)

now, if 2 moles of magnesium give -1204kJ

How much energy is given by 0.1479 moles

= (0.1479×-1204kJ)

=-89.0358kJ (don't forget the negative sign)

c) two molesof MgO produces -1204kJ of energy

then -234kJ will be produced by

=(-234kJ×2moles)/1204kJ

=0.3887moles

one mole of MgO weighs 24+16=40

therefore the mass produced is 0.3887moles×40=15.548grams

(d) we first find the number of moles of MgO in 40.3 grams

number of moles=mass/RFM

=40.3g/40= 1.0075moles

if 2 moles of MgO give 1204 kJ then decomposing 1.0075 moles requires

(1.0075 moles×1204kJ)/2=606.515kJ

4 0

3 years ago

A 25.0 ml sample of 0.150 m benzoic acid is titrated with a 0.150 m naoh solution. what is the ph at the equivalence point? the

Ad libitum [116K]

Solution:

At the equivalence point, moles NaOH = moles benzoic acid

HA + NaOH ==> NaA + H2O where HA is benzoic acid

At the equivalence point, all the benzoic acid ==> sodium benzoate

A^- + H2O ==> HA + OH- (again, A^- is the benzoate anion and HA is the weak acid benzoic acid)

Kb for benzoate = 1x10^-14/4.5x10^-4 = 2.22x10^-11

Kb = 2.22x10^-11 = [HA][OH-][A^-] = (x)(x)/0.150

x^2 = 3.33x10^-12

x = 1.8x10^-6 = [OH-]

pOH = -log [OH-] = 5.74

pH = 14 - pOH = 8.26

5 0

2 years ago

Read 2 more answers

According to the following reaction, how many grams of potassium sulfate will be formed upon the complete reaction of 23.8 grams

Alexxandr [17]

Answer: The mass of potassium sulfate that can be produced is 73.88 grams

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For KOH:

Given mass of KOH = 23.8 g

Molar mass of KOH = 56.1 g/mol

Putting values in equation 1, we get:

$\text{Moles of KOH}=\frac{23.8g}{56.1g/mol}=0.424mol$

The chemical equation for the reaction of KOH and potassium hydrogen sulfate follows:

$KHSO_4+KOH\rightarrow K_2SO_4+H_2O$

As, potassium hydrogen sulfate is present in excess. It is considered as an excess reagent.

KOH is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

1 mole of KOH produces 1 mole of potassium sulfate

So, 0.424 moles of KOH will produce = $\frac{1}{1}\times 0.424=0.424moles$ of potassium sulfate

Now, calculating the mass of potassium sulfate from equation 1, we get:

Molar mass of potassium sulfate = 174.26 g/mol

Moles of potassium sulfate = 0.424 moles

Putting values in equation 1, we get:

$0.424mol=\frac{\text{Mass of potassium sulfate}}{174.26g/mol}\\\\\text{Mass of potassium sulfate}=(0.424mol\times 174.26g/mol)=73.88g$

Hence, the mass of potassium sulfate that can be produced is 73.88 grams

8 0

3 years ago

When a sulfur atom gains its valence electrons to have 8, the charge on the resulting ion is

nikklg [1K]

When a sulfur atom gains its valence electrons to have 8, the charge on the resulting ion is stable since sulfur atom achieved the octet rule. An octet rule is the filling of 8 electrons in an atom.

8 0

3 years ago