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enyata [817]
4 years ago
8

The spread of which pathogens is most likely prevented by vaccines?

Chemistry
1 answer:
elena-14-01-66 [18.8K]4 years ago
3 0

Answer:

A

Explanation:

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Which statement describes how a basic coffee cup calorimeter works? A) It measures the mass of a substance given the specific he
fomenos
A calorimeter experiment is a set-up that provides insulation so that no heat escapes to the surroundings and all energy can be accounted for. It can be done at either constant volume or constant pressure. So, the answer to this is knowing the mass of water, the specific heat which is an empirical data, and the change in temperature which can be measured using a thermometer. This experiment could measure the mass of an unknown substance added or the specific heat of the substance or the calorimeter. <em>The answer is D.</em>
5 0
3 years ago
Read 2 more answers
Lt takes 4 hr 39 min for a 2.00-mg sample of radium-230 to decay to 0.25 mg. what is the half-life of radium-230?
Rufina [12.5K]
Radioactive decay => C = Co { e ^ (- kt) |

Data:

Co = 2.00 mg
C = 0.25 mg
t = 4 hr 39 min

Time conversion: 4 hr 39 min = 4.65 hr

1) Replace the data in the equation to find k

C = Co { e ^ (-kt) } => C / Co = e ^ (-kt) => -kt = ln { C / Co} => kt = ln {Co / C}

=> k = ln {Co / C} / t =  ln {2.00mg / 0.25mg} / 4.65 hr = 0.44719

2) Use C / Co  = 1/2 to find the hallf-life

C / Co = e ^ (-kt) => -kt = ln (C / Co)

=> -kt = ln (1/2) => kt = ln(2) => t = ln (2) / k

t = ln(2) / 0.44719 = 1.55 hr.

Answer: 1.55 hr
6 0
4 years ago
The spontaneous reaction that occurs when the cell in the picture operates is as follows: 2Ag+ + Cd(s) à 2 Ag(s) + Cd2+ (A) Volt
murzikaleks [220]

The question is incomplete, the remaining part of the question is

Which of the above occurs for each of the following circumstances?

A 50-milliliter sample of a 2-molar Cd(NO3)2 solution is added to the left beaker.

Answer:

Voltage decreases but remains > zero.

Explanation:

Given the balanced redox reaction equation:

2Ag^+(aq) + Cd(s) ---------------> 2 Ag(s) + Cd^2+(aq)

Concentration affects the cell voltage according to Nernst equation. Change in concentration must lead to a change in cell Voltage.

As the concentration of the Cd(NO3)2 solution is increased, voltage decreases because of the increase in the concentration values but voltages remains above zero.

6 0
4 years ago
Draw the structure of the major organic product isolated from the reaction of 1-hexyne with sodium amide in liquid ammonia follo
77julia77 [94]

Answer:check explanation and attached file/picture

Explanation:

Alkynes are hydrocarbons and they are very acidic because of hybridization effect(the more acidic the s-character is, the more acidic it is going to be).

The reaction of 1-hexyne with sodium amide in liquid ammonia is a form of deprotonation 'reaction' to form acetylide. Due to the acidic nature of the terminal hydrogen atom, terminal alkynes do form metallic derivatives by the replacement of the terminal hydrogens. The equation of Reaction is given below.

C6H10 + NaNH2( in liquidNH3) ------------> C6H9Na + H-NH2.

The acetylide is a bae and a very good nucleophile.

The reaction is then followed by the addition of 1-bromobutane. This reaction is used for the production of longer chain alkynes. The equation of Reaction is attached in the picture.

3 0
3 years ago
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What is known as the amount of<br> mass in a given volume?
Ganezh [65]

Answer:

Density

Explanation:

Density is a measure of how much mass is contained in a given volume

3 0
3 years ago
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