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3 years ago

13

Mallory combines two chemicals and notices that each chemical retains its original properties. What did Mallory form?

1 answer:

Advocard [28]3 years ago

7 0

Answer:

A mixture

Explanation:

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What is instantaneous acceleration?A. how fast a speed is changing at a specific instant B. how fast a velocity is changing at a

joja [24]

If i had to answer i would choose a hope this helps

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2 years ago

Be sure to answer all parts. What is the [H3O+] and the pH of a buffer that consists of 0.26 M HNO2 and 0.89 M KNO2? (K, of HNO2

Aleksandr-060686 [28]

Answer : The $H_3O^+$ ion concentration is, $1.12\times 10^{-3}M$ and the pH of a buffer is, 2.95

Explanation : Given,

$K_a=7.1\times 10^{-4}$

Concentration of $HNO_2$ (weak acid)= 0.26 M

Concentration of $KNO_2$ (conjugate base or salt)= 0.89 M

First we have to calculate the value of $pK_a$ .

The expression used for the calculation of $pK_a$ is,

$pK_a=-\log (K_a)$

Now put the value of $K_a$ in this expression, we get:

$pK_a=-\log (7.1\times 10^{-4})$

$pK_a=4-\log (7.1)$

$pK_a=3.15$

Now we have to calculate the pH of the solution.

Using Henderson Hesselbach equation :

$pH=pK_a+\log \frac{[Salt]}{[Acid]}$

$pH=pK_a+\log \frac{[KNO_2]}{[HNO_2]}$

Now put all the given values in this expression, we get:

$pH=3.15+\log (\frac{0.89}{0.26})$

$pH=2.95$

The pH of a buffer is, 2.95

Now we have to calculate the $H_3O^+$ ion concentration.

$pH=-\log [H_3O^+]$

$2.95=-\log [H_3O^+]$

$[H_3O^+]=1.12\times 10^{-3}M$

The $H_3O^+$ ion concentration is, $1.12\times 10^{-3}M$

4 0

3 years ago

If the neutral atom of an element has only 4 valence electrons it must be in which group? 1. IVB 2. VA 3. VIIA 4. VIA 5. IVA 6.

lisabon 2012 [21]

Answer:option

Option 5..IVA

Explanation:

5 0

3 years ago

Please answer, with explanation. Thanks!

nadya68 [22]

Answer:

Explanation:

a = 40.1 g of Ca

Number of moles = mass / molar mass

Number of moles = 40.1 g/ 40.1 g/mol

Number of moles = 1 mol

b = 11.5 g Na

Number of moles = mass / molar mass

Number of moles = 11.5 g/ 23 g/mol

Number of moles = 0.5 mol

c = 5.87 g Ni

Number of moles = mass / molar mass

Number of moles = 5.87 g/ 58.7 g/mol

Number of moles = 0.1 mol

d = 150 g of S

Number of moles = mass / molar mass

Number of moles = 150 g/ 32 g/mol

Number of moles = 4.7 mol

e = 2.65 g Fe

Number of moles = mass / molar mass

Number of moles = 2.65 g/ 55.85 g/mol

Number of moles = 0.05 mol

f = 0.00750 g Ag

Number of moles = mass / molar mass

Number of moles = 0.00750 g/ 107.9 g/mol

Number of moles = 6.95 × 10⁻⁵ mol

g = 2.25 × 10²⁵ atoms Zn

1 mole = 6.022 × 10²³ atoms

1 mol / 6.022 × 10²³ atoms × 2.25 × 10²⁵ atoms

0.17 × 2.25 × 10²⁵ moles

38.25 moles

h = 50 atoms of Ba

1 mole = 6.022 × 10²³ atoms

1 mol / 6.022 × 10²³ atoms ×50 atoms

0.17 × 10²³ × 50 moles

8.5 × 10²³ moles

6 0

3 years ago

The specific heat of copper is 0.40 joules/ g °c. How much heat is needed in joules to change the temperature of a 55 gram subst

Snezhnost [94]

Answer : The amount of heat needed is, 1188 J

Explanation :

Formula used :

$q=m\times c\times (T_2-T_1)$

where,

q = heat needed = ?

m = mass of copper = 55 g

c = specific heat capacity of copper = $0.40J/g^oC$

$T_1$ = initial temperature = $20.0^oC$

$T_2$ = final temperature = $74.0^oC$

Now put all the given values in the above formula, we get:

$q=55g\times 0.40J/g^oC\times (74.0-20.0)^oC$

$q=1188J$

Thus, the amount of heat needed is, 1188 J

3 0

3 years ago