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strojnjashka [21]
3 years ago
11

Help please!!

Chemistry
1 answer:
frez [133]3 years ago
7 0

Answer:

6.25%

Explanation:

Given data:

Half life of lutetium-117 = 6.75 days

Percentage remaining after 27 days = ?

Solution;

Number of half lives = Time elapsed / half life

Number of half lives = 27 days / 6.75 days

Number of half lives = 4

At time zero = 100%

At first half life = 100%/2 = 50%

At second half life = 50%/2 = 25%

At 3rd half life = 25%/2 = 12.5%

At 4th half life = 12.5%/2 = 6.25%

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tatyana61 [14]
Proton is the answer
8 0
3 years ago
how many mL of a 3.5 M sodium hydroxide will be needed to neutralize 15mL of a 4.3 M hydrochloric acid solution?
kobusy [5.1K]
Step 1 : write a valanced equation..
NaOH + HCl 》NaCl + H2O

Step 2 : find the number of mole of HCl..
1000 ml ..contains 4.3 mole
15ml... (4.3÷1000)×15 =...

Stem 3 : use mole ratio....
HCl : NaOH
1 : 1
So mole is same as calculated above...

Step 4 :
3.5 mole of NaOH is in 1000ml
(4.3÷1000)×15 mole is in ....


Do the calculation
6 0
3 years ago
An FM radio station broadcasts electromagnetic radiation at a frequency of 103.4 MHz (megahertz; MHz =106s–1). Calculate the w
kap26 [50]

Answer:

Wavelength=2.899\ m

Explanation:

The relation between frequency and wavelength is shown below as:

c=frequency\times Wavelength

c is the speed of light having value 2.998\times 10^8\ m/s

Given, Frequency = 103.4 MHz = 103.4\times 10^{6}\ Hz  ( as 1 MHz = 10⁶ Hz)

Thus, Wavelength is:

Wavelength=\frac{c}{Frequency}

Wavelength=\frac{2.998\times 10^8}{103.4\times 10^{6}}\ m

Wavelength=2.899\ m

5 0
3 years ago
In this task, you’ll observe a chemical reaction between baking soda and vinegar in water. write a hypothesis to predict the rel
Archy [21]

Answer:

Increase in the concentration of the reactants (vinegar and baking soda) leads to an increase in the rate of reaction (more volume of CO2 is evolved within a shorter time)

Explanation:

The chemical reaction between baking soda and vinegar in water is shown in the chemical reaction equation below;

NaHCO3(aq) + CH3COOH(aq) ----->CO2(g) + H2O(l) + CH3COONa(aq)

The chemical name of baking soda is sodium bicarbonate (NaHCO3) while vineager is a dilute acetic acid (CH3COOH) solution. This reaction provides a very easy set up in which we can study the effect of concentration on the rate of chemical reaction.

We must have it behind our minds that increase in the concentration of reactant species increases the rate of chemical reaction. Secondly, the rate of the reaction between baking soda and vinegar can be monitored by observing the volume of CO2 evolved and how quickly it evolves from the reaction mixture.

We can now postulate a hypothesis which states that; 'increase in the concentration of the reactants (vinegar and baking soda) leads to an increase in the rate of reaction (more volume of CO2 is evolved within a shorter time).'

If we go ahead to subject this hypothesis to experimental test, it will be confirmed to be true because a greater volume of CO2 will be evolved within a shorter time as the concentration of the reactants increases.

3 0
3 years ago
Based on the equation, determine what happens to the period, T, as the frequency increases.
ryzh [129]
The answer is c but it might be b it’s be
4 0
3 years ago
Read 2 more answers
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