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babymother [125]
3 years ago
12

If a weight lifter is holding barbells above his head, what does he have to do to perform work?

Chemistry
1 answer:
grandymaker [24]3 years ago
6 0

Answer:

For work to be done there must be 2 conditions to be followed:

(i) Force must be applied

(ii) displacement in the direction of force.

So if there is no force or displacement there is no work done. Since there is no displacement, as there is no initial and final position, no work is done. If he moves to a different position, work is done.

You might be interested in
Just Lemons Lemonade Recipe Equation:
zalisa [80]

Answer:

Explanation:

Hello!

<em>Complete text:</em>

<em>Honors Stoichiometry Activity WorksheetInstructions: </em>

<em>Activity Two: Just Lemons, Inc. Production</em>

<em>Here's a one-batch sample of Just Lemons lemonade production. Determine the percent yield and amount of leftover ingredients for lemonade production and place your answers in the data chart.</em>

<em>Hint: Complete stoichiometry calculations for each ingredient to determine the theoretical yield. Complete a limiting reactant-to-excess reactant calculation for both excess ingredients. </em>

<em>Water 946.36 g </em>

<em>Sugar 196.86 g </em>

<em>Lemon Juice 193.37 g </em>

<em>Lemonade 2050.25g</em>

<em>Leftover Ingredients?</em>

<em>Just Lemons Lemonade Recipe Equation:</em>

<em>2 water + sugar + lemon juice = 4 lemonade</em>

<em>Mole conversion factors:</em>

<em>1 mole of water = 1 cup = 236.59 g</em>

<em>1 mole of sugar = 1 cup = 225 g</em>

<em>1 mole of lemon juice = 1 cup = 257.83 g</em>

<em>1 mole of lemonade = 1 cup = 719.42 g</em>

You have the information on the ingredients used to produce one batch of lemonade and the amount of lemonade produced. To determine which ingredients be leftovers, you have to determine first, which one is the limiting reactant, i.e. the ingredient that will be used up first.

According to the recipe, to make 4 moles of lemonade, you use 2 moles of water, one mole of sugar and one mole of lemon juice, expressed in grams:

2 water  + sugar + lemon juice = 4 lemonade

2*(236.59) + 225g + 257.83g  = 4*(719.42)g

    473.18g + 225g + 257.83g = 2877.68g

So for every 2877.68g of lemonade made, they use 473.18g of water, 225g of sugar, and 257.83g of lemon juice.

You know that they made a batch of 2050.25g, so to detect the limiting reactant, first, you have to calculate, in theory, how much of each ingredient you need to make the given amount of lemonade:

Use cross multiplication

<u>Water:</u>

2877.68g lemonade → 473.18g water

2050.25g lemonade → X= (2050.25*473.18)/2877.68= 337.12g water

Following the recipe, to elaborate 2050.25g of lemonade, you need to use 337.12g of water.

<u>Sugar:</u>

2877.68g lemonade → 225g sugar

2050.25g lemonade → X= (2050.25*225)/2877.68= 160.30g sugar.

To elaborate 2050.25f of lemonade you need to use 160.30g of sugar.

<u>Lemon juice:</u>

2877.68g lemonade → 257.83g lemon juice

2050.25g lemonade → X= (2050.25*257.83)/2877.68= 183.69g lemon juice.

To elaborate 2050.25f of lemonade you need to use 183.69g lemon juice.

Available ingredients vs. theoretical yields for 2050.25g of lemonade:

Water 946.36 g → 337.12g

Sugar 196.86 g → 160.30g

Lemon Juice 193.37 g → 183.69g

The lemon juice will be the first ingredient to be used up, there will be a surplus of water and sugar.

I hope this helps!

7 0
4 years ago
How much heat is transferred when 7.19 grams of H2 reacts with excess nitrogen, according to the following equation: N2(g) + 3 H
nikdorinn [45]

Answer:

Q=54.8kJ

Explanation:

Hello there!

In this case, according to the given chemical reaction, it is possible for us to realize that the 46.2 kJ of energy are given per mole of reaction, which are related to 3 moles of hydrogen; Thus, we can calculate the energy per mole of hydrogen as shown below:

\Delta H=\frac{46.2kJ}{mol} *\frac{1mol}{3molH_2}\\\\ \Delta H=15.4\frac{kJ}{molH_2}

Now, to calculate the total energy, we convert the grams to moles of hydrogen as shown below:

Q=7.19gH_2*\frac{1molH_2}{2.02gmolH_2}*15.4\frac{kJ}{molH_2} \\\\Q=54.8kJ

Best regards!

5 0
3 years ago
Which statement accurately describes the chemical symbol of an element?
sweet [91]

Answer:

always begins with a capital letter

Explanation:

quizlet

6 0
3 years ago
Read 2 more answers
which of the following equations depicts a balanced equation, Na2CO3+2HCl=2NaCl+CO2+H2O, NaCO3+HCl=2NaCl+CO2+1H2O, 2Na2CO3+3HCl=
SashulF [63]

Explanation:

The first one is balanced equation

8 0
3 years ago
Read 2 more answers
How is the formation of covalent bonds similar to kids sharing markers? how is it different? if possible, discuss your answer wi
vagabundo [1.1K]
A covalent bond means shared electrons between atoms. This is similar to kids sharing markers because the markers (electrons) are being shared between the kids (atoms). Covalent bonds are different than this metaphor because 1) the electrons are constantly moving about while the kids can steal and keep the markers and 2) the electrons and atoms are physically smaller
5 0
3 years ago
Read 2 more answers
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