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Burka [1]
3 years ago
14

Ned is designing an experiment to test which hand sanitizer kills the most E. coli bacteria. In order for Ned's results to be va

lid, what must he do?
THE SUBJECT IS SCIENCE
Chemistry
2 answers:
sergiy2304 [10]3 years ago
4 0

Answer:

So the correct answer is "Test the hand sanitizers on bacterial colonies that are kept in the exact same environmental conditions, such as temperature and light level"

Explanation:

There are several ways to make sure the results of an investigation are valid. First, you and others can try to repeat the experiment. In addition, if it is a controlled experiment, you can make sure you have a control, only one independent variable, at least one dependent variable, and constants.

For Ned's results to be valid, he needs to test the hand sanitizers on bacterial colonies that are kept in the exact same environmental conditions, such as temperature and light level.

Molodets [167]3 years ago
3 0
Need more info please 
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Answer:

10 neutrons

This isotope of fluorine has 9 protons, 9 electrons and 10 neutrons.

Explanation:

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What is the shorthand notation (i.e., line notation) that best represents a complete electrochemical cell for the following galv
ruslelena [56]

Answer:

Sn^2+(aq)/Sn^3+(aq)//F2(g)/2F-(aq)

Explanation:

In writing the shorthand notation for an electrochemical cell, the oxidation half cell is shown on the left hand side and the reduction half cell is shown on the right hand side. The oxidation half equation reflects electron loss while the reduction half equation reflects electron gain.

5 0
4 years ago
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!

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How do you solve a double replacement reaction?
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And they would switch places to form a new compounds or products. Look at the Example!

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Solar Energy

Wind Energy

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Here are 3 energy sources that don't cause pollution, <em>I hope this helps.</em>
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