Ask question

Ask question

All categories

3 years ago

15

1. a substance with a pH of 3

2 answers:

Elenna [48]3 years ago

6 0

1. E
2. B
3. D
4. A
5. C

dem82 [27]3 years ago

6 0

Answer: 1. a substance with a pH of 3: acid

2. a substance with a pH of 10: base

3. a substance with a pH of 7: neutral

4. an indicator: phenolphthalein

5. a scale that represents the concentration of $H_3O^+$ , 0-14: pH scale

Explanation:-

pH or pOH is the measure of acidity or alkalinity of a solution.

pH is calculated by taking negative logarithm of hydrogen ion concentration and pOH is calculated by taking negative logarithm of hydroxide ion concentration.

On the pH scale ranging from 0 to 14 , Acids have pH ranging from 0 to 6.9, bases have pH ranging from 7.1 to 14 and neutral solutions have pH equal to 7.

$pH=-\log [H^+]$

$pOH=-log[OH^-]$

$pH+pOH=14$

Indicators show a change or appearance in color at particular pH. Phenolphthalein is one such acid base indicator which shows pink color in basic solutions and colorless in acidic solutions.

You might be interested in

How lift force works in CER format

Step2247 [10]

The really good answer is 30cm CER format

3 0

3 years ago

What is the diameter of uranus in si units?

Colt1911 [192]

D. 51,118 km is the diameter

7 0

3 years ago

A freshly prepared sample of radioactive isotope has an activity of 10 mCi. After 4 hours, its activity is 8 mCi. Find: (a) the

Maurinko [17]

Answer:

(a). The decay constant is $1.55\times10^{-5}\ s^{-1}$

The half life is 11.3 hr.

(b). The value of N₀ is $2.38\times10^{11}\ nuclei$

(c). The sample's activity is 1.87 mCi.

Explanation:

Given that,

Activity $R_{0}=10\ mCi$

Time $t_{1}=4\ hours$

Activity R= 8 mCi

(a). We need to calculate the decay constant

Using formula of activity

$R=R_{0}e^{-\lambda t}$

$\lambda=\dfrac{1}{t}ln(\dfrac{R_{0}}{R})$

Put the value into the formula

$\lambda=\dfrac{1}{4\times3600}ln(\dfrac{10}{8})$

$\lambda=0.0000154\ s^{-1}$

$\lambda=1.55\times10^{-5}\ s^{-1}$

We need to calculate the half life

Using formula of half life

$T_{\dfrac{1}{2}}=\dfrac{ln(2)}{\lambda}$

Put the value into the formula

$T_{\dfrac{1}{2}}=\dfrac{ln(2)}{1.55\times10^{-5}}$

$T_{\dfrac{1}{2}}=44.719\times10^{3}\ s$

$T_{\dfrac{1}{2}}=11.3\ hr$

(b). We need to calculate the value of N₀

Using formula of $N_{0}$

$N_{0}=\dfrac{3.70\times10^{6}}{\lambda}$

Put the value into the formula

$N_{0}=\dfrac{3.70\times10^{6}}{1.55\times10^{-5}}$

$N_{0}=2.38\times10^{11}\ nuclei$

(c). We need to calculate the sample's activity

Using formula of activity

$R=R_{0}e^{-\lambda\times t}$

Put the value intyo the formula

$R=10e^{-(1.55\times10^{-5}\times30\times3600)}$

$R=1.87\ mCi$

Hence, (a). The decay constant is $1.55\times10^{-5}\ s^{-1}$

The half life is 11.3 hr.

(b). The value of N₀ is $2.38\times10^{11}\ nuclei$

(c). The sample's activity is 1.87 mCi.

4 0

4 years ago

Where should an object be placed in front of a concave mirror’s principal axis to form an image that is real, inverted, larger t

malfutka [58]

<em> I believe the answer is letter C.</em>

8 0

3 years ago

Read 2 more answers

what material can be stored in a container but can also flow from one container to another and it forms powder after some time

Greeley [361]

Answer:

I think it is gas.

PLEASE MARK ME BRAINLIEST

4 0

3 years ago