Answer:
Explanation:
Since we are given the mass, specific heat, and change in temperature, we should use this formula for heat:
The substance's mass is 450.0 grams, the specific heat is 1.264 J/g°C, and the change in temperature is 7.1 °C.
Substitute the values into the formula.
Multiply the first 2 values together. The grams will cancel out.
Multiply again. This time, the degrees Celsius cancel out.
<u>4038.48 Joules</u> of heat energy are released.
HM, I think the answer would be D. This is just a guess, so please use it if ou want to answer D it's ok :D
These are the answer options of this question and the comments about their validity:
<span>A) It dictates that the number of molecules on each side of a chemical equation must be the same.
False: the number of molecules can change. Take this simple reaction for example:
2H2(g) + O2 -> 2H2O
You start with 3 molecules, 2 molecules of H2 and 1 molecule of O2, and end with 2 molecules of water. Then the number of molecules of each side is different.
B) It dictates that the number of atoms of each element must be the same on both sides of a chemical equation.
TRUE: in a chemical reaction the atoms remain being the same at start and at the end of the process. Given that each atom has a characteristic mass, their conservation implies the law of conservation mass.
C) It states that the mass of the reactants must remain constant in order for a chemical reaction to proceed.
FALSE. The mass of the reactants changes during a chemical reaction, while they transform into the products.
D) It does not apply to chemical reactions.
FALSE: It is an important law used in the calculus related with chemical reactions.
</span>
Answer:
40 g NaOH
Step-by-step explanation:x
To make 500 mL of a 2 mol·L⁻¹ solution, the technician must measure the correct mass of NaOH.
Step 1. Calculate the <em>moles of NaOH
</em>
c = n/V Multiply both sides by V
n = Vc
c = 2 mol·L⁻¹
V =0.5 L
n = 0.5 × 2
n = 1 mol NaOH
Step 2. Calculate the <em>mass of NaOH
</em>
The molar mass of NaOH is 40.00 g/mol.
m = 1 × 40.00/1
m = <em>40 g NaOH
</em>
The technician must measure <em>40 g of NaOH</em>.
It is an alpha decay because when this phenomena occurs an atomic nucleus emits an alpha particle (helium nucleus) and consequentially decays into another atom with a mass number that is reduced by four an atomic number that is reduced by 2 two. The helium atom consists of two protons and two neutrons.
Therefore, the answer is <span>alpha decay because alpha particles have two protons and two neutrons</span>
